System for relative positioning of access points in a real time locating system

ABSTRACT

A system is described for relative positioning of access points in a real time locating system. The system may include a memory, interface, and processor. The memory may store layout information for a work area which includes architectural and infrastructure attributes. The processor may determine a number of access points to position in the work area based on the architectural attributes. The processor may determine a placement of a test tag in the work area based on the infrastructure attributes. The processor may determine a positioning of the access points in the work area which substantially maximizes coverage and accuracy of locating the test tag in the work area. The processor may determine a repositioning of one of the access points when the coverage and accuracy do not satisfy a threshold. The processor may provide a graphical representation of the positioning of the access points, when the threshold is satisfied.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No.61/234,134, filed on Aug. 14, 2009, and is a continuation-in-part ofU.S. Non-provisional application Ser. No. 12/634,110, filed on Dec. 9,2009, both of which are incorporated by reference herein.

TECHNICAL FIELD

The present description relates generally to a system and method,generally referred to as a system, for relative positioning of accesspoints in a real time locating system, and more particularly, but notexclusively, to relative positioning of access points in a real timelocating system which substantially maximizes coverage and accuracy.

BACKGROUND

Individuals working in hazardous environments, such as refineries,chemical plants, or nuclear power plants, may be exposed to hazardousmaterials, such as hazardous gases, chemical compounds, or radiation.Prolonged exposure to hazardous materials may lead to sickness or death.Thus, each individual entering a hazardous environment may be requiredto wear a badge containing a sensor which detects the level of exposureof the individual to the hazardous materials. The badge may alert theindividual if the individual is being exposed to harmful levels ofhazardous materials. When the badge alerts the individual, theindividual is expected to vacate the contaminated area containing thehazardous materials, thereby reducing their exposure to the hazardousmaterials. However, in some instances the individual may not vacate thecontaminated area and may continue to be exposed to the hazardousmaterials for a prolonged period of time. For example, the individualmay not notice the alert, or may simply ignore the alert. The prolongedexposure to the hazardous materials may cause the individual to sufferfrom serious sickness or death.

SUMMARY

A system for relative positioning of access points in a real timelocating system may include a memory, an interface, and a processor. Thememory may be connected to the processor and the interface and may storelayout information of a work area which includes architectural andinfrastructure attributes of the work area. The processor may receivethe layout information of the work area and determine a number of accesspoints to position in the work area based on the architecturalattributes. The processor may determine a placement in the work area ofa test radio frequency tag based on the infrastructure attributes. Theprocessor may determine a positioning of the plurality of access pointsin the work area which substantially maximizes a coverage and anaccuracy of locating the test radio frequency tag in the work area. Theprocessor may determine a repositioning of one of the access points whenthe coverage and accuracy do not satisfy a threshold. The processor mayprovide a graphical representation of the positioning of the accesspoints in the work area, relative to one another, when the coverage andthe accuracy satisfy the threshold.

Other systems, methods, features and advantages will be, or will become,apparent to one with skill in the art upon examination of the followingfigures and detailed description. It is intended that all suchadditional systems, methods, features and advantages be included withinthis description, be within the scope of the embodiments, and beprotected by the following claims and be defined by the followingclaims. Further aspects and advantages are discussed below inconjunction with the description.

BRIEF DESCRIPTION OF THE DRAWINGS

The system and/or method may be better understood with reference to thefollowing drawings and description. Non-limiting and non-exhaustivedescriptions are described with reference to the following drawings. Thecomponents in the figures are not necessarily to scale, emphasis insteadbeing placed upon illustrating principles. In the figures, likereferenced numerals may refer to like parts throughout the differentfigures unless otherwise specified.

FIG. 1 is a block diagram of a general overview of a system for relativepositioning of access points in a real time locating system.

FIG. 2 is a block diagram of a network environment implementing thesystem of FIG. 1 or other systems for relative positioning of accesspoints in a real time locating system.

FIG. 3 is a block diagram of an exemplary network architectureimplementing the system of FIG. 1 or other systems for relativepositioning of access points in a real time locating system.

FIG. 4 is a block diagram of a sensor network implementing the system ofFIG. 1 or other systems for relative positioning of access points in areal time locating system.

FIG. 5A is a block diagram of an exemplary gas detection and locatingdevice with wired components in the system of FIG. 1 or other systemsfor relative positioning of access points in a real time locatingsystem.

FIG. 5B is a block diagram of an exemplary gas detection device withwireless components in the system of FIG. 1 or other systems forrelative positioning of access points in a real time locating system.

FIG. 6 is a block diagram of an exemplary mobile access pointmeasurement and location unit in the system of FIG. 1 or other systemsfor relative positioning of access points in a real time locatingsystem.

FIG. 7 is a block diagram of an exemplary mobile access pointmeasurement and location unit in the system of FIG. 1 or other systemsfor relative positioning of access points in a real time locatingsystem.

FIG. 8 is a flowchart illustrating the general operations of relativepositioning of access points in the system of FIG. 1, or other systemsfor relative positioning of access points in a real time locatingsystem.

FIG. 9 is a flowchart illustrating the generation of an access pointconfiguration in the system of FIG. 1, or other systems for relativepositioning of access points in a real time locating system.

FIG. 10 is a flowchart illustrating the detection of gas by a gasdetection and locating device in the system of FIG. 1, or other systemsfor relative positioning of access points in a real time locatingsystem.

FIG. 11 is a flowchart illustrating a panic button activation by a gasdetection and locating device in the system of FIG. 1, or other systemsfor relative positioning of access points in a real time locatingsystem.

FIG. 12 is a flowchart illustrating a lack of motion detection by a gasdetection and locating device in the system of FIG. 1, or other systemsfor relative positioning of access points in a real time locatingsystem.

FIG. 13 is a flowchart illustrating an alarm received from a gasdetection and locating device in the system of FIG. 1, or other systemsfor relative positioning of access points in a real time locatingsystem.

FIG. 14 is a flowchart illustrating high risk area prediction in thesystem of FIG. 1, or other systems for relative positioning of accesspoints in a real time locating system.

FIG. 15 is a screenshot of a user interface for viewing access pointcoverage of a facility in the system of FIG. 1, or other systems forrelative positioning of access points in a real time locating system.

FIG. 16 is a screenshot of a user interface for viewing access pointcoverage of individual access points in the system of FIG. 1, or othersystems for relative positioning of access points in a real timelocating system.

FIG. 17 is a screenshot of a user interface for viewing access pointlocating accuracy in the system of FIG. 1, or other systems for relativepositioning of access points in a real time locating system.

FIG. 18 is a screenshot of a user interface displaying a placementanalysis report in the system of FIG. 1, or other systems for relativepositioning of access points in a real time locating system.

FIG. 19 is a screenshot of a user interface for monitoring the locationand gas exposure level of users in the system of FIG. 1, or othersystems for relative positioning of access points in a real timelocating system.

FIG. 20 is a screenshot of a user interface for monitoring gas exposurelevels in the system of FIG. 1, or other systems for relativepositioning of access points in a real time locating system.

FIG. 21 is a screenshot of a user interface for monitoring the locationand gas exposure level of users using a positioning system in the systemof FIG. 1, or other systems for relative positioning of access points ina real time locating system.

FIG. 22 is an illustration of a general computer system that may be usedin the systems of FIG. 2, FIG. 3, or other systems for relativepositioning of access points in a real time locating system.

DETAILED DESCRIPTION

A system and method, generally referred to as a system, may relate torelative positioning of access points in a real time locating system,and more particularly, but not exclusively, relative positioning ofaccess points in a real time locating system for substantiallymaximizing coverage and accuracy. For explanatory purposes, the detaileddescription discusses relative positioning of access points for a realtime locating and gas exposure monitoring system. However, the systemmay be used for relative positioning of access points in any system forwhich substantially maximizing coverage and accuracy would bebeneficial. The principles described herein may be embodied in manydifferent forms.

The system may allow an organization to determine a relative positioningof access points in a work area such that the access pointssubstantially maximize the wireless coverage and accuracy in the workarea. For example, a real time locating and gas exposure monitoringsystem may allow an organization to monitor the location of individualsin a work area, and the level of exposure of each individual to one ormore hazardous materials. However, if portions of a work area do nothave comprehensive wireless coverage, the real time locating and gasexposure monitoring system may be unable to monitor individuals in theentire work area. Furthermore, the real time locating and gas exposuremonitoring system may be unable to accurately locate individuals in thework area if the relative positioning of the access points does notprovide for substantially accurate locating. Thus, the system forrelative positioning of access points may allow an organization tosubstantially maximize coverage and locating accuracy of a work area.

The system may allow an organization to effectively position accesspoints in order to improve visibility into hazardous events forindividuals within a hazardous environment. An organization may usespecialized wireless (WiFi) enabled gas detectors, mesh wireless accesspoints, Real Time Location Services (RTLS), and alert monitoring systemsto relay gas levels and locations of individuals to a continuouslymonitored control console. The control console may alert operators viaaudible and visual alarms indicating specific gas thresholds, a panicbutton, and lack of motion events. The system may allow an organizationto effectively position the wireless access points based on one or morefactors, such as accuracy, wireless coverage, individual safety, systemreliability and cost.

The system may allow an organization to effectively position accesspoints in order to monitor the location of each individual in a workarea, and the level of exposure of each individual to one or morehazardous materials. Each individual entering the area may be providedwith a gas detection and real time locating device which communicatesthe gas exposure and location of the individual to a server. When thegas exposure of the individual meets an alarm threshold, the systemperforms one or more alarm handling actions, such as locating theindividual, initiating communication with the individual, alertingoperators in the vicinity of the individual, initiating communicationwith responders, or generally any actions which may be necessary torespond to the alarm. The gas detection and real time locating devicemay include a panic button, which, when activated by an individual,communicates an alarm to the server. The gas detection and real timelocating device may also detect when an individual fails to move for aperiod of time. The gas detection and real time locating device may senda local alert to the individual, such as by vibrating. If the individualdoes not respond to the local alert, the device may send an alarm to theserver. The gas detection and real time locating device may also includeadditional sensors to monitor other stimuli, such as biometric sensorsfor monitoring heart rate, blood pressure or other health relatedmeasures.

The system may allow the organization to effectively position accesspoints in order to quickly locate individuals exposed to harmful levelsof hazardous materials and evacuate the individuals from thecontaminated area. The system may allow the organization to expand theirgas detection network to include each individual carrying a gasdetection device in the work area. The expanded gas sensor network mayprovide the organization with advanced notice of gas leaks orcontamination and may allow the organization to quickly evacuate theindividuals located in the proximity of the contamination. The systemmay use a combination of network infrastructure and satellitepositioning systems to monitor the location of individuals in anindoor/outdoor work environment.

FIG. 1 provides a general overview of a system 100 for relativepositioning of access points in a real time locating system. Not all ofthe depicted components may be required, however, and someimplementations may include additional components. Variations in thearrangement and type of the components may be made without departingfrom the spirit or scope of the claims as set forth herein. Additional,different or fewer components may be provided.

The system 100 may include one or more users 120A-N, an operator 110,and a service provider 140. The users 120A-N may be employees of anorganization who work in a hazardous work environment, such as arefinery, a nuclear power plant, a chemical plant, a mine, or any otherhazardous work environment. The users 120A-N may be exposed to harmfullevels of one or more hazardous materials, such as hazardous gases,hazardous chemical compounds, or hazardous radiation while working inthe hazardous work environment. The users 120A-N may suffer fromsickness or death if they are exposed to harmful levels of the hazardousmaterials, such as hazardous gases, chemicals and/or nuclear particles.Alternatively or in addition, the users 120A-N may be deprived ofoxygen, such as in a mine, and may suffer from sickness or death fromlack of oxygen. The work environment, or work area, may include multiplestructures, such as buildings, and each building may include multiplelevels or floors. The work environment may further include one or moreoutdoor areas, and/or subterranean areas, such as a basement, tunnel orcave. The users 120A-N may be located in any of the structures or levelswithin the work environment.

The service provider 140 may provide the operator 110 with access to thesystem 100 for relative positioning of access points to maximizewireless coverage and location accuracy. The system 100 may analyze thearchitectural and infrastructure attributes to determine a relativepositioning of access points which substantially maximizes the wirelesscoverage and accuracy of the access points. Coverage may be a measure ofradio frequency signal propagation throughout an area, measured by aReceived Signal Strength Indicator (RSSI) value. Increased coverage maybe directly correlated to more accurate location tracking. Thearchitectural attributes of the work area may include the number oflevels of the work area, the height of each level, the average amount offoot traffic in each area, the wireless frequency of the environment(and structures which may affect the wireless frequency, such asmetallic or concrete objects), and generally any other attributes whichare related to, or affected by, the architectural design of the workarea. The infrastructure attributes may include the location of poweroutlets, the location of wired Ethernet outlets, such as for power overEthernet (PoE) functionality, or generally any other attributes whichmay be related to, or affected by, the infrastructure of the work area.The steps of determining the relative positioning of the access pointsis discussed in more detail in FIGS. 8-9 below. The operator 110 may useone or more mobile access point measurement and location units (MAMALs)to test the wireless coverage and accuracy. Exemplary MAMALs arediscussed in more detail in FIGS. 6 and 7 below. The service provider140 may provide the operator 110 with one or more user interfaces forviewing the coverage and accuracy of the access points. The system 100may also provide the operator 110 with a user interface which displays aconstruction estimate based on the determined number, and location, ofwireless access points, and a user interface which displays the workarea and the relative positioning of the access points within the workarea. Exemplary user interfaces are discussed in more detail in FIGS.15-18 below.

The users 120A-N may each wear a gas detection and locating device, suchas a badge or tag, which may include a sensor for monitoring theexposure of the users 120A-N to the hazardous materials, such ashazardous gases or chemical compounds. The badge may include a hazardousgas sensor, a locating device, and an interface, such as a networkinterface. The interface may transmit data describing the amount ofhazardous gas a user A 120A has been exposed to, and the location of theuser A 120A, to a central server. The hazardous gas exposure andlocation data of the user A 120A may be transmitted to the centralserver on a periodic basis, such as every minute. The period of timebetween transmissions of each user 120A-N may be manually configurableand/or may be automatically configurable by the central server. Forexample, if the central server detects that a user A 120A has entered anarea with a high concentration of hazardous gases, the central servermay automatically instruct the badge to transmit the gas exposureinformation of the user A 120A more frequently. Alternatively or inaddition, if the hazardous gas exposure of the user A 120A isapproaching dangerous levels, the central server may automaticallyinstruct the badge to transmit the gas exposure data more frequently.For example, there may be one or more gas exposure thresholds which,when met by a user A 120A, may cause the badge of the user A 120A toincrease the frequency of the transmissions of gas exposure information.

Alternatively or in addition, users 120A-N in a nuclear power plant workenvironment may wear a radiation detector and locating device. Theradiation detector and locating device may include a Geiger counter fordetermining the exposure of the users 120A-N to radiation. Alternativelyor in addition, users 120A-N working in a chemical plant may wearchemical detectors and locating devices which may detect whether theusers 120A-N are being exposed to harmful levels of chemical compounds.Alternatively or in addition, users 120A-N working in a mine may weargas detectors and locating devices which detect whether the users 120A-Nare being exposed to enough, or too much, oxygen. In general, thesensor, or detector, worn by the users 120A-N may be determined based onthe potential hazards of the work area. The badge should be worn withina breathing zone of the user A 120A, such as within ten inches of thenose and/or mouth of the user A 120A.

Alternatively or in addition, the badge may function as anidentification device for the user A 120A. For example, the badge mayinclude a radio frequency identification tag, which may communicate withone or more radio frequency readers. The readers may be in communicationwith one or more access points, such as doorways. Each reader may eitherallow or deny the user A 120A to pass through the access point, based onthe permissions associated with the radio frequency identification tagof the user A 120A. The radio frequency identification readers may beused as supplemental location devices. That is, the readers may be incommunication with the service provider server 240, such as via thenetworks 230, 235, and may communicate the location and identificationof the user A 120A to the service provider sever 240 when the radiofrequency identification tag of the user A 120A passes by the reader.Thus, the current location of the user A 120A may be supplemented orverified when the user A 120A passes by one of the radio frequencyidentification readers.

The badge may further include a location processor, such as apositioning system processor, for determining information describing thelocation of a user A 120A and communicating the location information tothe central server. The positioning processor may determine the locationof the user A 120A based on data received from a satellite, such as aglobal positioning system (GPS). Exemplary badges including locationprocessors are discussed in more detail in FIGS. 5A-B below.Alternatively or in addition, if the user A 120A is located indoors, andthe badge is not able to receive data from a satellite, the location ofthe user A 120A may be identified by the network infrastructure used inthe work environment. The components of the network infrastructure arediscussed in more detail in FIG. 2 below. The system 100 may be capableof seamlessly switching between identifying the location of the user A120A through the GPS data or through the network infrastructure, therebyallowing the system 100 to track the location of the user A 120A as theymove from indoors to outdoors and vice-versa. If the user A 120A cannotbe located through the GPS data or the network infrastructure, the userA 120A may be shown as “out of range” and may reconnect when the user A120A is back within range of the system 100.

If a badge determines that a user A 120A has been exposed to harmfullevels of the hazardous gas, the badge may initiate a local alarm, suchas by vibrating, flashing, or sounding an alarm, such as a beep, and maycommunicate an alarm to the central server including the currentlocation of the user A 120A and the level of gas exposure of the user A120A. Alternatively or in addition, the central server may determinethat the user A 120A has been exposed to harmful levels of the hazardousgases and may communicate a gas exposure alarm to the badge. Detectionof harmful levels of hazardous gas by a badge is discussed in moredetail in FIG. 6 below.

The badges may also include a panic button, which may be activated by auser A 120A when the user A 120A believes there may be a problem. When auser A 120A activates the panic button, the badge may communicate analarm to the central server including the location of the user A 120Aand the gas exposure of the user A 120A. The badge may also initiate alocal alarm. The activation of a panic button on a badge is discussed inmore detail in FIG. 7 below.

The badge may also detect if the user A 120A has not moved for a periodof time. If the badge detects that the user A 120A has not moved for aperiod of time, the badge may initiate a local alarm, such as byvibrating, flashing, or sounding a noise. The user A 120A may cancel thelack of motion alarm by pressing a cancel button on the tag or touchingtheir badge. If the user A 120A does not press the cancel button withina period of time, then the badge may communicate an alarm to the centralserver. Alternatively or in addition, the central server may monitor themovement of the user A 120A and may send a lack of motion alarm to thebadge. An alarm related to a lack of motion of the user A 120A may bereferred to as a “man down” alarm, or alert, because the user A 120A ispresumed to be motionless.

The service provider 140 may provide an organization with the centralserver, referred to as the service provider server 240 in FIG. 2 below,which receives the location data items and the gas exposure data itemsfrom the badges of the users 120A-N. Alternatively or in addition, theservice provider 140 may provide the badges to the users 120A-N. Forexample, the service provider 140 may be consulting organization whichprovides the badges, and the central server, to the organization inorder to enable the organization to monitor the location and gasexposure of their employees. The service provider 140 may customize theserver with vendor software for monitoring the location and gas exposureof the users 120A-N. The user interfaces of exemplary monitoringsoftware applications are shown in FIGS. 11-16 below.

The server may receive data transmissions from the badges which mayinclude a location identifier identifying the location of the users120A-N and the gas exposure of the users 120A-N. The location of theusers 120A-N may be determined by a positioning system on the badge, ormay be determined by the network infrastructure. The location of theusers 120A-N may also include the elevation of the users 120A-N. Thelocation identifier may include coordinates, such longitude and latitudecoordinates. The server may determine when a user A 120A has beenexposed to harmful levels of gas and may activate an alarm for the userA 120A. Alternatively or in addition, the server may receive an alarmdata item from a badge when the badge detects harmful levels ofhazardous gases.

The operator 110 may be a person who operates the server provided by theservice provider server 140. Alternatively or in addition, the operator110 may be a machine or automated process. The operator 110 may monitorthe users 120A-N and may be alerted by the server when one of the users120A-N is exposed to harmful levels of the hazardous gases. The operatormay attempt to initiate contact with the user A 120A, such as over awalkie-talkie or over a mobile phone. The operator 110 may also initiatecommunication with emergency personnel, such as responders, ifnecessary. Alternatively or in addition, there may be one or moreoperators spread throughout the workplace that may be in communicationwith the server, such as via a mobile device or other computing device.

In operation, when the server receives an alarm data item or initiatesan alarm, such as for a user A 120A who is exposed to harmful levels ofa hazardous gas, the server may perform a series of alarm handlingactions based on the received alarm data item. The alarm handlingactions may include alerting the operator 110 to the alarm, attemptingto open a communication channel to the user A 120A, identifying thelocation of the user A 120A in the facility, and communicate the alarmand the location of the user A 120A to any other operators in thefacility. The server may also determine whether emergency responders,such as medical personnel, are required based on the level of gasexposure of the user A 120A, and may automatically initiatecommunication with the emergency responders. The reception of alarm databy the server is discussed in more detail in FIG. 9 below.

Alternatively or in addition, the service provider 140 may provide aprepackaged solution for real time locating and gas detection which mayfurther include add-on applications. The add-on applications may includevideo surveillance, unified communications, asset tracking, mobileworker, fixed gas monitoring, gas cloud simulation, and/or productivity,such as worker scheduling and time card reporting. The solution mayinclude a hardware installation template/approach which may describe aprocess for optimized infrastructure deployment. The solution mayinclude a solution deployment template, which may describe a processused to quickly and accurately deploy the solution. The solution mayinclude change management, which may describe business process changesrequired by the personnel in the work area, such as a plant or refinery,in order to properly use the solution. The solution may include acommunication template which may describe a process used to ensurecomprehensive and optimized testing. The solution may include costingmodel template which may describe a cost estimating model for deploymentbased on plant layout. The solution may include an ongoing supportaccelerator, which may describe the management process required for longterm support. The service provider 140 may also provide ongoingvalidation of the solution, such as a process for ensuring thatsolution/application is functioning properly over time.

Alternatively or in addition, the service provider 140 may identify asingle point of contact which may include negotiated vendor contractsand defined vendor responsibilities. The service provider server 240 mayalso provide z-axis calibration. For example, the service providerserver 240 may calibrate on the ground and may calibrate in the air.

Alternatively or in addition, the service provider 140 may provide oneor more productivity process improvements. For example, the serviceprovider 140 may provide a change maintenance process for managingvolatile organic compound (VOC) emissions using wireless gas sensors.The service provider 140 may also provide a change maintenance processfor managing volatile organic compound (VOC) transmissions usingwireless gas sensors. The service provider 140 may provide architectureto support enterprise level work efficiencies, as existing solutions maybe plant/location specific an unable to scale on their own. The serviceprovider 140 may provide process improvements aimed atworkforce/resource sharing. The service provider 140 may providecontractor accountability, such as by linking to PEOPLESOFT time andlabor reporting to create automatedaccountability/dashboards/reconciliation and analysis.

Alternatively or in addition, the gas detection devices worn by theusers 120A-N may be used in conjunction with stationary wireless gassensors in order to build a wireless sensor network. An exemplarywireless sensor network is discussed in more detail in FIG. 4 below. Thewireless sensor network may be used to predict the movement of ahazardous gas through a work area. Predicting the movement of thehazardous gas may allow an organization to pro-actively alert the users120A-N to imminent danger. Using a wireless sensor network to predictthe movement of hazardous gas is discussed in more detail in FIG. 10below.

Alternatively or in addition, the service provider 140 may provide ‘bestprocess’ modeling. For example, the service provider 140 may model idealwork performances physically and through video-ip camera network on aWiFi infrastructure. The service provider 140 may offer playback of theperformances to workforce/contractors for safety improvements and workefficiency/quality.

FIG. 2 provides a simplified view of a network environment 200implementing the system of FIG. 1 or other systems for relativepositioning of access points in a real time locating system. Not all ofthe depicted components may be required, however, and someimplementations may include additional components not shown in thefigure. Variations in the arrangement and type of the components may bemade without departing from the spirit or scope of the claims as setforth herein. Additional, different or fewer components may be provided.

The network environment 200 may include one or more users 120A-N, gasdetection and locating devices (“badges”) 220A-N, network components225A-N, an operator 110, a computing device 210, a service providerserver 240, a third party server 250, a data store 245, a wirelesslocation server 260, and networks 230, 235. Some or all of the serviceprovider server 240, the third party server 250, and the wirelesslocation server 260 may be in communication with each other by way ofnetwork 235. The users 120A-N may be located across various parts of afacility, or work area, or an organization. The users 120A-B may belocated within a structure 270, the user A 120A being on the secondfloor 272 of the structure 270, and the user B 120B being on the firstfloor 271 of the structure 270. The user N 120N may be outdoors 273.

The networks 230, 235 may include wide area networks (WAN), such as theInternet, local area networks (LAN), metropolitan area networks, or anyother networks that may allow for data communication. The network 230may include the Internet and may include all or part of network 235;network 235 may include all or part of network 230. The networks 230,235 may be divided into sub-networks. The sub-networks may allow accessto all of the other components connected to the networks 230, 235 in thesystem 200, or the sub-networks may restrict access between thecomponents connected to the networks 230, 235. The network 235 may beregarded as a public or private network connection and may include, forexample, a virtual private network or an encryption or other securitymechanism employed over the public Internet, or the like.

The badges 220A-N may be gas detection and locating devices, such asthose shown in FIGS. 5A-B below. The badges 220A-N may include a sensor,such as for detecting gas, and a communication interface, such as tocommunicate over the networks 230, 235. The sensors may be automaticallysynchronized by the service provider server 240.

Alternatively or in addition, the users 120A-N may receive the badges220A-N when they are entering a hazardous work area. In this example,the service provider server 240 may scan an identification badge of auser A 120A, such as by bar code or by radio frequency identification,and may then scan a badge 220A. The badge 220A may then be associatedwith the user A 120A, and the user A 120A may use the badge 220A whilein the hazardous work area. When the user A 120A leaves the hazardouswork area, they may return the badge 220A and the badge 220A may beunassociated with the user A 120A. For example, the user A 120A may dockthe badge 220A into a charger. Upon docking the badge 220A into thecharger, the service provider server 240 may remove the associationbetween the badge 220A and the user A 120A. The badge 220A may then beassociated with any of the users 120A-N who enters the hazardous workarea. Alternatively or in addition, the service provider server 240 mayalso retrieve any sensor data stored on the badge 220A prior to removingthe association from the user A 120A.

The badges 220A-N may communicate over the networks 230, 235 via thenetwork components 225A-N. Each of the network components 225A-N mayrepresent one or more wireless routers, wired routers, switches,controllers, or generally any network components which may be used toprovide communications over the networks 230, 235. For example, thenetwork components 225A-N may be CISCO AIRONET Access Points and/orCISCO Wireless LAN Controllers. The network components 225A-N may becapable of identifying the location of the badges 220A-N andcommunicating the location of the badges to the service provider server240. In the example where the network components 225A-N are accesspoints, the access points may be strategically placed throughout thefacility 270 and/or work area to ensure the entire area of the facilityand/or work place is within range of one of the access points. The userN 120N located outdoors 273 may be out of the range of the wirelessnetwork, and may communicate with the service provider server 240 viacellular telephone towers. Alternatively, the location of the user N120N, or the users 120A-B may be determined based on triangulatingsignals received by cellular telephone towers, third party locationservices, such as GOOGLE LATITUDE™, or generally any mechanism fordetermining the location of the user N 120N. Alternatively or inaddition, the user N 120N located outdoors 273 may be located remotelyfrom the work area. In this example, the badge 220N may communicate withthe service provider server 240 via a satellite data connection.Alternatively or in addition, the location of the user N 120N may betracked based on a satellite positioning system, such as the globalpositioning system (GPS).

The service provider server 240 may include one or more of thefollowing: an application server, a mobile application server, a datastore, a database server, and a middleware server. The service providerserver 240 may exist on one machine or may be running in a distributedconfiguration on one or more machines. The service provider server 240,the computing device 210, the badges 220A-N, and the wireless locationserver 260 may be one or more computing devices of various kinds, suchas the computing device in FIG. 22. Such computing devices may generallyinclude any device that may be configured to perform computation andthat may be capable of sending and receiving data communications by wayof one or more wired and/or wireless communication interfaces. Suchdevices may be configured to communicate in accordance with any of avariety of network protocols, including but not limited to protocolswithin the Transmission Control Protocol/Internet Protocol (TCP/IP)protocol suite. For example, the computing device 210 may employ theHypertext Transfer Protocol (“HTTP”) to request information, such as aweb page, from a web server, which may be a process executing on theservice provider server 240.

There may be several configurations of database servers, applicationservers, mobile application servers, and middleware applicationsincluded in the service provider server 240. The data store 245 may bepart of the service provider server 240 and may be a database server,such as MICROSOFT SQL SERVER®, ORACLE®, IBM DB2®, SQLITE®, or any otherdatabase software, relational or otherwise. The application server maybe APACHE TOMCAT®, MICROSOFT IIS®, ADOBE COLDFUSION®, or any otherapplication server that supports communication protocols.

The third party server 250 may be a server which provides external dataor services to the service provider server 240. For example, the thirdparty server 250 may be part of an emergency response system. Theservice provider server 240 may request emergency assistance for a userA 120A by communicating with the third party server 250. Alternativelyor in addition, the service provider server 240 may provide services orinformation to the service provider server 240. For example, the thirdparty server 250 may belong to a neighboring business. The serviceprovider server 240 may notify the third party server 250 of gas leaks,such as gas clouds, which may affect the geographical location of theneighboring business based on data received from the badges 220A-N orother gas sensors.

The wireless location server 260 may be a network component capable ofidentifying the location of the badges 220A-N, and consequently, thelocation of the users 120A-N. The wireless location server 260 mayutilize information received from the network components 225A-N, and/orthe badges 220A-N, to determine the location of the users 120A-N. Forexample, the wireless location server 260 may be a CISCO WIRELESSLOCATION APPLIANCE.

The networks 230, 235 may be configured to couple one computing device,such as the badges 220A-N, to another computing device, such as theservice provider server 240, to enable communication of data between thedevices. The networks 230, 235 may generally be enabled to employ anyform of machine-readable media for communicating information from onedevice to another. Each of networks 230, 235 may include one or more ofa wireless network, a wired network, a local area network (LAN), a widearea network (WAN), a direct connection such as through a UniversalSerial Bus (USB) port, and the like, and may include the set ofinterconnected networks that make up the Internet. If wireless thenetworks 230, 235 may be cellular telephone networks, 802.11, 802.16,802.20, or WiMax networks, or generally any wireless network. Thenetworks 230, 235 may include any communication method by whichinformation may travel between computing devices.

The operator 110 may utilize the computing device 110 to monitor thelocation and the gas exposure of the users 120A-N. The computing device110 may be configured to run one or more computing applications, such asAEROSCOUT MOBILE VIEW, CISCO WIRELESS CONTROL SYSTEM (WCS) NAVIGATOR orINDUSTRIAL SCIENTIFIC INET CONTROL. The computing applications mayassist the operator 110 with monitoring the location and gas exposure ofthe users 120A-N. The computing applications may utilize Simple ObjectAccess Protocol/Extensible Markup Language (SOAP/XML) applicationprogramming interfaces (API) to communicate data with one another. Forexample, the AEROSCOUT MOBILE VIEW computing application may retrievedata describing the location of the users 120A-N from the CISCO WIRELESSCONTROL SYSTEM using one or more SOAP/XML APIs.

The operator 110 and the computing device 210 may be located within thework area of the organization. Alternatively or in addition, theoperator 110 and computing device 210 may be located external to thework area, such as within a remote monitoring facility. The remotemonitoring facility may monitor the gas exposure and location of users120A-N in multiple work areas of multiple organizations. The computingdevice 210 may provide the operator 110 with access to variousapplications, such as Cisco™ Wireless Controller System (WCS) version6.0.132.0, Cisco™ Mobility Services Engine version 6.0.85.0, AeroScout™Mobileview System Manager version 3.2 (MSE 6.0), AeroScout™ MobileviewAnalyzer version 1.5, Secure Copy™ WwinSCP version 4.2.7, and/orAeroScout™ Tag Manager version 4.02.22.

In operation, a gas sensor in a badge A 220A may detect the level ofexposure of a user A 120A to one or more hazardous gases. The badge A220A may communicate the amount of gas exposure of the user A 120A, andthe location of the user A 120A, to the service provider server 240 on aperiodic basis. The location of the user A 120A may be determined basedon a positioning system, such as a global positioning system (GPS).Alternatively or in addition, if the users 120A-B are located indoors,or the location information can otherwise not be retrieved from apositioning system, the location information may be determined by thenetwork infrastructure. In this example, the wireless location server260 may determine the location of a user A 120A, such as bytriangulating the wireless data signal from the badge A 220A to thenetwork components 225A-N, and may communicate the location of the userA 120A to the service provider server 240. Alternatively, the networkcomponents 225A-N may include a radio frequency (RF) reader and maydetect the location of the badges 220A-N by triangulating a radiofrequency (RF) received from the badges 220A-N.

If the badge A 220A detects that the user A 120A has been exposed to aharmful level of a hazardous gas, the badge A 220A may communicate analarm to the service provider server 240. The alarm may include theamount of gas the user A 120A has been exposed to and the location ofthe user A 120A. There may be multiple levels of alarms depending uponthe determined danger of the user A 120A. For example, if the user A120A is not responding to a lack of motion alarm, then an emergencyalarm may be issued. However, if the user A 120A is entering apotentially dangerous area, then a warning alarm may be initiated.

The service provider server 240 may receive the alarm data, may transmitan automatic confirmation back to the badge A 120A confirming receipt ofthe alarm, and may perform one or more alarm response actions based onthe alarm data. For example, the service provider server 240 may attemptto initiate communication with the user A 120A, may communicate thealarm to an operator 110 in close proximity of the user A 120A, or,depending on the level of gas exposure, may contact emergency responsepersonnel. The alarm response actions of the service provider server 240are discussed in more detail in FIG. 9 below.

Alternatively or in addition, the service provider server 240 maymonitor the gas exposure information received from the gas detection andlocating devices 225A-N and other gas detection devices. The serviceprovider server 240 may analyze the received data to determine areaswhere the gas level may be dangerously high. If the service providerserver 240 detects a user A 120A entering one of the dangerous areas,the service provider server 240 may automatically transmit an alarm tothe gas detection and locating device of the user A 120A.

Alternatively or in addition, a plant performance solution, such asACCENTURE PLANT PERFORMANCE SOLUTION, may be used as an overarchinggraphical user interface which may be used by the management of theorganization. The plant performance solution may be running on theservice provider server 240 and/or the computing device 210. The plantperformance solution may provide overall plant performance management,such as a heat map display of the alarms. Alternatively or in addition,the service provider server 240 may provide a new graphical userinterface depending upon a gap assessment.

Alternatively or in addition, the service provider server 240 mayperform one or more analytics on the data collected from the gasdetection and locating devices 220A-N and other sensors in the workarea. For example, the service provider server 240 may predict high riskwork events by integrating the received data with real-timehistorical/unit level data. Based on the analyzed data, the serviceprovider server 240 may provide proactive alerts to the users 120A-N,managers and/or operators. The service provider server 240 may correlategas releases to unplanned processes for historical analysis, may planfor future events and may continuously improve the system 100.Generally, the service provider server 240 may maintain historical datagathered from the gas detection and locating devices 220A-N and othersensors to identify trends, such as exposure levels per area, exposurelevels per user, or generally any trends.

Alternatively or in addition, the network environment 200 may be testedon a periodic basis, such as each month, to ensure the entire system 100is operating properly. The network environment 200 may further includeadditional sensors, such as wireless magnetic temperature sensors, whichare in communication with the service provider server 240, such as viathe networks 230, 235. Alternatively or in addition, the data receivedfrom the gas detection and locating devices 225A-N and/or other sensors,referred to as telemetry data, may be integrated into MSE. Alternativelyor in addition, the system 100 and/or one or more components of thenetwork environment 200 may be integrated into DCS.

Alternatively or in addition, there may be multiple operators 110operating multiple computing devices 210. In this example the serviceprovider server 240 may determine the proper operator 110 for receivingeach alarm, such as based on geographic location, language spoken, orother factors.

Alternatively or in addition, the network environment 200 may furtherinclude supplemental tags for assistance with determined dead spots. Adead spot may be a location where there is no gas detection or nowireless infrastructure. Alternatively or in addition, the serviceprovider server 240 may include the Experion DCS which may be used foralarming of either gas sensor based alarms of alarms initiate by theactivation of the panic button.

Alternatively or in addition, each alarm may indicate the reason for thealarm on both the gas detection and locating devices 220A-N and thecomputing device 210 of the operator 110. The alarm on the gas detectionand locating devices may include an audible tone which may differ foreach type of alarm.

FIG. 3 is a block diagram of an exemplary network architecture 300implementing the system of FIG. 1 or other systems for relativepositioning of access points in a real time locating system. Not all ofthe depicted components may be required, however, and someimplementations may include additional components not shown in thefigure. Variations in the arrangement and type of the components may bemade without departing from the spirit or scope of the claims as setforth herein. Additional, different or fewer components may be provided.

The network architecture 300 may include a wireless location server 260,a wireless control system 310, a service provider server 240, amultilayer switch 312, a route switch processor 314, a network 330, arouter 350, a wireless LAN controller 352, a wireless services module354, a wireless LAN controller module 356, a switch 358, wireless accesspoints 360, Wi-Fi tags 370, stationary wireless sensors 375, orchokepoints, users 120A-N and badges 220A-N. For example, the wirelesslocation server 260 may be a CISCO WIRELESS LOCATION APPLIANCE, thewireless control system 310 may be a CISCO WIRELESS CONTROL SYSTEM, thewireless LAN controller 352 may be a CISCO WIRELESS LAN CONTROLLER, andthe wireless access points 360 may be lightweight wireless accesspoints, such as CISCO AIRONET ACCESS POINTS. Alternatively, or inaddition, the wireless access points 360 may be CAPWAP wireless accesspoints. Alternatively or in addition, the access points 360 may includemobile access point measurement and location units (MAMALs) when thepositioning of the wireless access points 360 is being determined.MAMALs are discussed in more detail in FIG. 6 and FIG. 7 below.

The stationary wireless sensors 375 may include gas sensors, such ashazardous gas sensors, and may be mounted in areas requiring monitoring.The stationary wireless sensors 375 may detect the presence of the Wi-Fitags 370 and/or the badges 220A-N. Alternatively or in addition, if thestationary wireless sensors 375 include gas sensors, the stationarywireless sensors 375 may detect the presence of hazardous gases. Thesensors of the stationary wireless sensors 375, and the sensors of thebadges 220A-N, may function as a sensor network, such as the sensornetwork described in FIG. 4 below. The controllers 352, 356, may bestationary, or may be mobile, such as located inside a vehicle. In thecase of a mobile controller 352, 356, the controller 352, 356 is mobileacross high latency links.

FIG. 4 is a block diagram of a sensor network 400 implementing thesystem of FIG. 1 or other systems for relative positioning of accesspoints in a real time locating system. Not all of the depictedcomponents may be required, however, and some implementations mayinclude additional components not shown in the figure. Variations in thearrangement and type of the components may be made without departingfrom the spirit or scope of the claims as set forth herein. Additional,different or fewer components may be provided.

The sensor network 400 may include a facility 410, a network 230, and aservice provider server 240. The facility may include rooms 415A-D. RoomA 415 A may include a user B 120B, a badge B 220B, and a stationarywireless sensor 375. Room B 415B may include a stationary wirelesssensor 375. Room C 415C may include a user A 120A, and a badge A 120A.Room D 415D may include a stationary wireless sensor 375. In operation,the badges 220A-B and stationary wireless sensors 375 may detecthazardous gas levels and may communicate the hazardous gas levels to theservice provider server 240 through the network 230. The sensor network400 may also include one or more network components which are not shownin FIG. 4, such as the network components shown in FIG. 3.

The stationary wireless sensors 375 may be mounted in rooms or areaswhich are not frequently visited by the users 120A-N. For example, theroom B 415B and the room D 415D may not be frequently visited by theusers 120A-N. Alternatively, sensors 375 may not be placed in rooms orareas where users 120A-N are frequently present. For rooms or areaswhere users 120A-N are frequently present, the badges 220A-N of theusers 120A-N may act as substitutes for the sensors 375. That is, sincethe users 120A-N wearing badges 220A-N containing sensors are frequentlypresent in these areas, there may not be a need for additionalstationary sensors 375. Alternatively or in addition, stationarywireless sensors 375 may be placed in rooms where users 120A-N arefrequently present if these areas require a higher level of fidelity inthe detection of hazardous gases. In this instance, the service providerserver 240 may be able to identify both the specific room wherehazardous gas is detected and a particular region of the room wherehazardous gas is detected.

The sensor network 400 may also be used to predict the movement of ahazardous gas. For example, the differing levels of a hazardous gasdetected by the sensors 375 and the badges 220A-B, along with the rateof change in the levels of the hazardous gas, may be used to predict themovement of the hazardous gas. Predicting the movement of the hazardousgas may allow the service provider server 240 to transmit pro-activealarms to the badges 220A-N of the users 120A-N. That is, the serviceprovider server 240 may transmit alarms to users 120A-N that are notcurrently in danger, but have a high likelihood of being in danger in ashort period of time, such as 5 minutes. Using the sensor network topredict high risk areas is discussed in more detail in FIG. 10 below.

FIG. 5A provides an illustration of an exemplary gas detection andlocating device 500A with wired components in the system of FIG. 1 orother systems for relative positioning of access points in a real timelocating system. Not all of the depicted components may be required,however, and some implementations may include additional components notshown in the figure. Variations in the arrangement and type of thecomponents may be made without departing from the spirit or scope of theclaims as set forth herein. Additional, different or fewer componentsmay be provided.

The gas detection and locating device 500A may be used as one of thebadges 220A-N in FIGS. 2-4 above. The gas detection and locating device500A may include a casing 505, a location device 510, a gas detector520, and a connector 530. The location device 510 may include a wiredinterface 512, a location processor 514, and an interface 516, such as anetwork interface. The gas detector 520 may include a wired interface522, a gas sensor 524, and a sensor 526. In one example, the locationdevice 510 may be a LENEL badge, or location sensor, or an AEROSCOUTTAG, such as an AEROSCOUT T3 TAG, an AEROSCOUT T4B tag, an AEROSCOUT T5SENSOR TAG, or an AEROSCOUT T6 GPS TAG, and the gas detector 520 may bean INDUSTRIAL SCIENTIFIC GAS BADGE, such as an INDUSTRIAL SCIENTIFICGASBADGE PLUS, an INDUSTRIAL SCIENTIFIC MX-4, an INDUSTRIAL SCIENTIFICMX-6, or an INDUSTRIAL SCIENTIFIC GASBADGE PRO. The casing 505 may bethe original housing of the location device 510. In this example, thegas detector 520 would be added to the casing of the location device510. Alternatively, the casing 505 may be the original housing of thegas detector 520. In this example, the location device 510 would beadded to the casing of the gas detector 520.

The location device 510 and the gas detector 520 may be in communicationvia the connector 530. For example, the wired interface 512 of thelocation device may be connected to the connector 530, and the connector530 may be connected to the wired interface 522 of the gas detector. Theconnector 530 may be a wired connector, such as an RS-232 serialconnection cable, a wire, or generally any connector capable of couplingthe location device 510 to the gas detector 520. The gas detector 520may communicate information determined by the gas sensor 524 and/or thesensor 526, such as the amount of gas the user A 120A has been exposedto, to the location device 510.

The location processor 514 of the location device 510 may determine thelocation of the gas detection and locating device 500A, such as througha positioning system. For example, the location processor 514 may be incommunication with one or more GPS satellites, and may receive locationinformation from the GPS satellites. The location processor 514 maycommunicate the location information to the interface 516. The interface516 may enable the gas detection and locating device 500A to communicatewith the network 230. The interface 516 may be a wireless networkconnection, a wired network connection, an infrared network connection,or generally any connection capable of providing communication betweenthe gas detection and location device 500A and the network 230. When thelocation device 510 receives sensor information from the gas detector,the location device 510 may communicate the sensor information, and thecurrent location of the gas detection and locating device 500A to theservice provider server 240 via the network 230.

The gas sensor 524 of the gas detector 520 may be a sensor capable ofdetecting the amount of hazardous gas a user is being exposed to. Thegas sensor 524 may be capable of detecting one or more hazardous gases,such as hydrogen sulfide (H₂S), nitrogen dioxide (NO₂), sulfur dioxide(SO₂), carbon dioxide (CO₂), carbon monoxide (CO), oxygen (O₂), LEL, orgenerally any gases. In order to ensure the gas sensor 524 is accuratelyidentifying the amount of gas a user A 120A is being exposed to, the gasdetection and locating device 500A may be worn close to the mouth and/ornose of the user A 120A, such as within ten inches of the mouth of theuser A 120A. The gas sensor 524 may communicate the amount of gasdetected to the wired interface 522. The wired interface 522 maycommunicate the amount of gas detected to the location device 510.Alternatively or in addition, the gas sensor 524, or a coupledprocessor, may process the amount of gas detected to determine if theamount satisfies an alarm threshold. If the gas sensor 524 determinesthat the amount satisfies the alarm threshold, the gas sensor 524 maycommunicate an alarm to the location device 510 via the wired interface522. Alternatively or in addition, the location processor 514, or acoupled processor, may determine if the amount of gas detected satisfiesthe alarm threshold.

The sensor 526 may detect other stimuli, such as biometric informationor heat exhaustion information. The sensor 526 may communicate thebiometric information to the location device 510 via the wired interface522. Alternatively or in addition, the sensor 526 may detect whether theuser A 120A is moving. For example, the sensor 526 may detect that theuser A 120A has not moved for an extended period of time. In thisinstance, the sensor 526 may activate a local alarm on the gas detectingand locating device 500A. The local alarm may cause the gas detectionand locating device 500A to vibrate, light up, beep, or otherwise notifythe user A 120A of the lack of movement. The user A 120A may respond tothe local alarm by pressing a button on the outside of the casing 505.If the user A 120A does not press the button within a period of time,such as ten seconds, the sensor 526 may communicate an alarm to theservice provider server 240 via the location device 510.

Alternatively or in addition, the outside of the casing 505 of the gasdetection and locating device 500A may include one or more buttons,lights, sensors, and/or displays. For example, the outside of the casing505 may have a panic button that can be activated by the user A 120A inthe case of an emergency. The casing 505 may also have a cancel button,which may allow the user A 120A to cancel an alarm, such as an alarmcaused by lack of motion. The casing 505 may also include one or morelights, or displays, which may light up or change colors when the user A120A is exposed to different levels of gases. Alternatively or inaddition, the outside of the casing 505 may include a display which maydisplay the amount of gas the user A 120A is currently being exposed toand whether the current level of exposure is dangerous to the health ofthe user A 120A. The display may also display the reason an alarm hasbeen initiated by the gas detection and locating device 500A.

Alternatively or in addition, the gas detection and locating device 500Amay be intrinsically safe, such as Class I, Division 2, simple and easyto use, reasonably sized, such as no longer than a mobile phone, andable to attach to a front pocket or helmet, such as generally within teninches of a breathing zone of a user A 120A.

FIG. 5B provides an illustration of an exemplary gas detection andlocating device 500B in the system of FIG. 1 or other systems forrelative positioning of access points in a real time locating system.Not all of the depicted components may be required, however, and someimplementations may include additional components not shown in thefigure. Variations in the arrangement and type of the components may bemade without departing from the spirit or scope of the claims as setforth herein. Additional, different or fewer components may be provided.

The gas detection and locating device 500B may be used as one of thebadges 220A-N in FIG. 2 above. The gas detection and locating device500B may include a location device 510 and a gas detector 520. Thelocation device 510 may include a wireless interface 518, a locationprocessor 514, and an interface 516. The gas detector 520 may include awireless interface 528, a gas sensor 524, and a sensor 526. In oneexample, the location device 510 may be an AEROSCOUT TAG, such as anAEROSCOUT T3 TAG, an AEROSCOUT T5 SENSOR TAG, or an AEROSCOUT T6 GPSTAG, and the gas detector 520 may be a INDUSTRIAL SCIENTIFIC GAS BADGE,such as an INDUSTRIAL SCIENTIFIC GASBADGE PLUS, an INDUSTRIAL SCIENTIFICMX-4, an INDUSTRIAL SCIENTIFIC MX-6, or an INDUSTRIAL SCIENTIFICGASBADGE PRO.

The location device 510 and the gas detector 520 may be in communicationvia the wireless interfaces 518, 528. The wireless interfaces 518, 528may communicate via one or more wireless communication protocols, suchas Bluetooth, infrared, Wi-Fi, wireless universal serial bus (USB),radio frequency, or generally any wireless communication protocol. Thegas detector 520 may communicate information determined by the gassensor 524 and/or the sensor 526, such as the amount of gas the user A120A has been exposed to, to the location device 510 via the wirelessinterfaces 518, 528. The wireless interfaces 518, 528, may allow for thelocation device 510 to be located remotely from the gas detector 520, onthe user A 120A. For example, the gas detector may be part of anidentification badge which may be within a certain distance of the mouthand/or nose of the user A 120A, such as ten inches. However, thelocation device 510, may be in the pocket of the user A 120A, or may beclipped to the belt of the user A 120A, thus reducing the size andweight of the identification badge.

The location processor 514 of the location device 510 may determine thelocation of the gas detection and locating device 500A, such as througha positioning system. For example, the location processor 514 may be incommunication with one or more GPS satellites, and may receive locationinformation from the GPS satellites. The location processor 514 maycommunicate the location information to the interface 516. The interface516 may enable the gas detection and locating device 500A to communicatewith the network 230. The interface 516 may be a wireless networkconnection, a wired network connection, an infrared network connection,or generally any connection capable of providing communication betweenthe gas detection and location device 500A and the network 230. When thelocation device 510 receives sensor information from the gas detector,the location device 510 may communicate the sensor information, and thecurrent location of the gas detection and locating device 500A to theservice provider server 240 via the network 230.

The gas sensor 524 of the gas detector 520 may be a sensor capable ofdetecting the amount of hazardous gas a user is being exposed to. Thegas sensor 524 may be capable of detecting one or more hazardous gases,such as hydrogen sulfide, nitrogen dioxide, sulfur dioxide, carbondioxide, carbon monoxide, or generally any gases. In order to ensure thegas sensor 524 is accurately identifying the amount of gas a user A 120Ais being exposed to, the gas detection and locating device 500A may beworn close to the mouth and/or nose of the user A 120A, such as withinten inches of the mouth of the user A 120A. The gas sensor 524 maycommunicate the amount of gas detected to the wired interface 522. Thewired interface 522 may communicate the amount of gas detected to thelocation device 510. Alternatively or in addition, the gas sensor 524,or a coupled processor, may process the amount of gas detected todetermine if the amount satisfies an alarm threshold. If the gas sensor524 determines that the amount satisfies the alarm threshold, the gassensor 524 may communicate an alarm to the location device 510 via thewired interface 522. Alternatively or in addition, the locationprocessor 514, or a coupled processor, may determine if the amount ofgas detected satisfies the alarm threshold.

The sensor 526 may detect other stimuli, such as biometric information.The sensor 526 may communicate the biometric information to the locationdevice 510 via the wired interface 522. Alternatively or in addition,the sensor 526 may detect whether the user A 120A is moving. Forexample, the sensor 526 may detect that the user A 120A has not movedfor an extended period of time. In this instance, the sensor 526 mayactivate a local alarm on the gas detecting and locating device 500A.The local alarm may cause the gas detection and locating device 500A tovibrate, light up, beep, or otherwise notify the user A 120A of the lackof movement. The user A 120A may respond to the local alarm by pressinga button on the outside of the location device 510 and/or the gasdetector 520. If the user A 120A does not press the button within aperiod of time, such as ten seconds, the sensor 526 may communicate analarm to the service provider server 240 via the location device 510.

Alternatively or in addition, the outside casing of the location device510 and/or the gas detector 520 may include one or more buttons, lights,sensors, and/or displays. For example, the outside casing of thelocation device 510 and/or the gas detector 520 may include a panicbutton that may be activated by the user A 120A in the case of anemergency. The outside casing of the location device 510 and/or the gasdetector 520 may also include a cancel button, which may allow the userA 120A to cancel an alarm, such as an alarm caused by lack of motion.The outside of the location device 510 and/or the gas detector 520 mayfurther include one or more lights, or displays, such as a liquidcrystal display (LCD) which may light up or change colors when the userA 120A is exposed to different levels of gases. Alternatively or inaddition, the outside casing of the location device 510 and/or the gasdetector 520 may include a display which may display the amount of gasthe user A 120A is currently being exposed to and whether the currentlevel of exposure is dangerous to the health of the user A 120A.

Alternatively or in addition the gas detector 520 may include aninterface, such as a network interface, for communicating gas data tothe service provider server 240. In this example, the gas detector 520and the location device 510 may be associated with a user A 120A. Forexample, there may be record in the data store 245 which associates anidentifier of the gas detector 520 and an identifier of the locationdevice 510 with an identifier of the user A 120A. The gas detector 520may communicate gas data and an identifier of the gas detector 520 tothe service provider server 240. The service provider server 240 may usethe identifier of the gas detector 520 to retrieve from the data store245 an identifier of the user A 120A associated with the gas detector520, and the location device 510 associated with the user A 120A. Theservice provider server 240 may then request location data from theidentified location device 510. Thus, the service provider server 240 isable to communicate individually with the gas detector 520 and thelocation device 510.

FIG. 6 is a block diagram of an exemplary mobile access pointmeasurement and location unit (MAMAL) 600 in the system of FIG. 1 orother systems for relative positioning of access points in a real timelocating system. Not all of the depicted components may be required,however, and some implementations may include additional components notshown in the figure. Variations in the arrangement and type of thecomponents may be made without departing from the spirit or scope of theclaims as set forth herein. Additional, different or fewer componentsmay be provided.

The MAMAL 600 may include an enclosure 610, one or more antennas 620,one or more access points, a power supply and one or more zip ties tosecure the antennas 620. For example, the enclosure 610 may be a ruggedenclosure such that the MAMAL can be transported to various workenvironments. The antennas 620 may include one or more 2.4 gigahertz 6dBi mast antennas and/or one or more 5.8 gigahertz 6 dBi mast antennas.The antennas 620 may further include one foot shielded cable extension.The access points may be any wireless access points, such as Cisco 1242AG access points. The access points may also include Power over Ethernetfunctionality, such as IEEE 802.3af Power over Ethernet (PoE). The powersupply may be a TerraWave MIMO site survey battery pack.

In operation, one or more MAMALs 600 may be used as a self-containedaccess points to deploy a temporary mesh network used for RF sitesurveying. The MAMAL 600 may be moved freely from structure tostructure, and work area to work area, without the need for in-linepower. One or more MAMALs 600 may also be used to rapidly deploy ameshed network for proof of concepts and pilots. A minimum number ofMAMALs 600 may be required for various sized work areas and/orstructures. For example, a minimum of three MAMALs may be needed forsite surveying with the guidelines of one MAMAL for every 10,000 squarefeet to cover.

FIG. 7 is a block diagram of an exemplary mobile access pointmeasurement and location unit (MAMAL) 700 in the system of FIG. 1 orother systems for relative positioning of access points in a real timelocating system. Not all of the depicted components may be required,however, and some implementations may include additional components notshown in the figure. Variations in the arrangement and type of thecomponents may be made without departing from the spirit or scope of theclaims as set forth herein. Additional, different or fewer componentsmay be provided.

The MAMAL 700 may include an enclosure 710, one or more wires 715, apower supply 720, one or more antennas, one or more access points, andone or more zip ties to secure the antennas. For example, the enclosure710 may be a rugged enclosure such that the MAMAL can be transported tovarious work environments. The power supply 720 may be a TerraWave MIMOsite survey battery pack. The wires 715 may be connected to the powersupply 720 and the one or more access points. The one or more accesspoints may be any wireless access points, such as Cisco 1242 AG accesspoints. The access points may also include Power over Ethernetfunctionality, such as IEEE 802.3af Power over Ethernet (PoE). Theantennas may include one or more 2.4 gigahertz 6 dBi mast antennasand/or one or more 5.8 gigahertz 6 dBi mast antennas. The antennas mayinclude one foot shielded cable extension.

In operation, one or more MAMALs 700 may be used as a self-containedaccess points to deploy a temporary mesh network used for RF sitesurveying. The MAMAL 700 may be moved freely from structure tostructure, and work area to work area, without the need for in-linepower. One or more MAMALs 700 may also be used to rapidly deploy ameshed network for proof of concepts and pilots. A minimum number ofMAMALs 700 may be required for various sized work areas and/orstructures. For example, a minimum of three MAMALs may be needed forsite surveying with the guidelines of one MAMAL for every 10,000 squarefeet to cover.

FIG. 8 is a flowchart illustrating the general operations of relativepositioning of access points in the system of FIG. 1, or other systemsfor relative positioning of access points in a real time locatingsystem. The steps of FIG. 8 are described as being performed by theservice provider server 240. However, the steps may be performed by theprocessor of the service provider server 240, or by any other hardwarecomponent of the service provider server 240. Alternatively the stepsmay be performed by an external hardware component.

At step 810, the service provider server 240 may retrieve the layout ofthe facility or work area, such as from the data store 245.Alternatively or in addition, the service provider server 240 mayreceive the layout of the facility from the third party server 250, orfrom the operator 110 via the computing device 210. Alternatively or inaddition, the service provider server 240 may also receive one or morebusiness requirements associated with the positioning of the accesspoints 360. For example, the business requirements may include locationaccuracy, such as no less than fifty feet, wireless coverage, individualsafety, system reliability, cost and deployment timeframe. The layout ofthe work area may include one or more architectural attributes, and oneor more infrastructure attributes.

At step 820, the service provider server 240 identifies the one or morearchitectural attributes of the layout. For example, the architecturalattributes may include the physical layout of the work area, such as thenumber of levels, the unit dimensions, key structures within the unit,such as boilers, pipe alleys, etc., hazardous areas, high foot trafficareas, or generally any attributes related to, or affected by, thearchitectural design of the work area. At step 830, the service providerserver 240 identifies the infrastructure attributes of the work area.For example, the infrastructure attributes may include network switchlocations, fiber or copper runs, lighting systems, backup power systems,power outlets, network outlets, or generally any attributes related to,or affected by, the infrastructure of the work area.

At step 840, the service provider server 240 may determine testlocations of tags, such as radio frequency identification tags, or thegas detection and locating devices 500A-B. The location of the test tagsmay be based on operator rounds and the high foot traffic areas of thework area, that is, areas where many individuals are expected to be. Thetags may be initialized and configured prior to placing them within thework area. The tags may be activated using a tag activator. The operatormay input the actual location of the test tags to the service providerserver 240, such that the actual locations can be compared against thelocations determined based on readings of the access points.

At step 850, the service provider server 240 may determine the numberand initial location of access points in the work area. The initialnumber of access points may be based on the overall square footage ofthe work area. The access points may be positioned using a top-downapproach. Elevated access points may be used to provide coverage on highlevels within the work area. The initial location of the access pointsmay be based on the architectural and infrastructure attributes of thework area. For example, access points may not be placed within closeproximity, such as eight feet, to large concrete or metal obstructionsidentified in the attributes. The positioning of the access points mayprovide line-of-sight coverage for high traffic walkways. Thepositioning of the access points may include a mixture of elevations,such as ground, mid-level and high. The access points may be positionedrelative to one another to form equilateral triangles or squares.Alternatively or in addition, the access points may form a circle orother polygons, such as rhombus, trapezoid, parallelograms, orrectangles. The positioning of the access points may avoid lines, asthey may provide less accuracy. The location and coverage of nearbyaccess points may be included in determining where to position an accesspoint. The access points may be positioned such that tags in the workarea receive good signal coverage from three or more access points. Theaccess points may be positioned such that the perimeter of the accesspoints closely coincides with the physical perimeter of the work area.The access points may be positioned close to, or inside of, the unitbattery limits. If the target accuracy is fifty meters, the accesspoints may not be placed more than twenty-five meters from physicalboundaries. The access points may be positioned such that two accesspoints in are not placed in the same location at different elevations.

Alternatively or in addition, the location of the tags may bere-determined once the access point locations are determined. Forexample, the location of test tags may be based on various proximitiesto access points. The test tags may also be distributed throughout theunit's battery limits, and at various elevations.

At step 870, the service provider server 240 may test the wirelesscoverage of the tags, and location accuracy, provided by the positioningof the access points. The operator 110 may place MAMALs in theidentified locations of the access points to test the tag coverage. Byusing the MAMALs, the operator may test portions of the work area, oneby one, without requiring access points for the entire work area. TheMAMALs may be reused for testing each portion, or partition, of the workarea. The service provider server 240 may access the readings of theMAMALs, such as via the network 230. The service provider server 240 mayperform multiple readings of the coverage, such as ten to twelve, usingdifferent locations of the access points or tags. Likewise, the serviceprovider server 240 may limit changes between recordings to a singleaccess point or tag movement to minimize variation between recordings.

The test tags may be used as points of reference within the system 100for taking RF measurements. For example, the operator 110 may providethe service provider server 240 with the actual location of a tag. Theservice provider server 240 may then test the accuracy of the accesspoints by determining whether the location provided by the access pointscoincides with the actual location of the tags. For example, theoperator 110 may identify a small, high elevation area within the workarea. The operator 110 may place a high density of tags around theidentified area. The service provider server 240 may then perform a teston the small area to determine the coverage and accuracy that may bepossible. Once the operator 110 is able to arrange the tags into anacceptable accuracy for the area, such as less than twenty meters, thetags may be moved to various places and elevations to determine anoverall reading. The small to large area approach may be executed fromthe top of the work area down.

The service provider server 240 may also generate one or more reportsrelated to testing the coverage and location accuracy of the accesspoints. For example, the service provider server 240 may generate aplacement analysis report. The placement analysis report may includeinformation describing multiple recordings, or readings, of the accesspoint coverage and location accuracy. For example, each recording may beanalyzed for coverage and location accuracy, such as by using the RSSIstrength, the average accuracy, access point placement descriptions, tagcoverage, or generally any other factors. An exemplary placementanalysis report is discussed in FIG. 18 below. Alternatively or inaddition, the service provider server 240 may provide one or more userinterfaces which provide a graphical display of the coverage andlocation accuracy results. Exemplary user interfaces displaying thecoverage and location accuracy results are discussed in more detail inFIGS. 15-17 below.

At step 875, the service provider server 240 may determine whether thetag coverage and location accuracy satisfy a threshold. The thresholdmay be determined based on one or more of individual safety, systemreliability, and cost. For example, the threshold may indicate that thecoverage should be at least −75 dBm (decibels (dB) of the measured powerreferenced to one milliwatt (mW)) for the entire work area.Alternatively, the threshold may indicate that each test tag should becovered by three or more access points with at least −75 dBm ofcoverage. The threshold may also indicate that the location accuracyshould be an average of twenty meters or less. The location accuracy maybe determined by comparing the actual location of the tags inputted bythe operator with the location of the tags determined from informationreceived from the access points. Alternatively, the threshold mayindicate that a substantially minimal number of tags may have coveragefrom less than three access points. The threshold may also indicate thatthe access points individual coverage analysis should be OK or better.

If, at step 875, the service provider server 240 determines that thecoverage and location accuracy does not satisfy the threshold, theservice provider server 240 moves to step 890. At step 890, the serviceprovider server 240 determines a repositioning of one or more of theaccess points based on the tested coverage and location accuracy. Forexample, if a first test tag tested with an accuracy and coverage abovethe threshold, and a nearby second test tag tested with an accuracy andcoverage below the threshold, then an access point between the two tagsmay be moved close to the second test tag. Alternatively or in addition,the service provider server 240 may determine that the threshold cannotbe met with the number of access points currently in the configuration.In this case, the service provider server 240 may add additional accesspoints to the configuration and may position the access points nearbytags for which the coverage or location accuracy does not meet thethreshold.

If, at step 875, the service provider server 240 determines that thelocation accuracy and coverage of the work area, or of the individualtest tags, satisfies the threshold, the service provider server 240moves to step 880. At step 880, the service provider may generate andprovide the determined layout of the access points. The determinedlayout may include the placement of each access point, including theheight of each access point.

Alternatively or in addition, the service provider server 240 mayprovide one or more verification tests prior to finalizing the layout ofthe access points. The verification tests may be designed to ensure thebest case accuracy is achieved as well as mimic the production systemduring additional testing, such as a walk around testing. Theverification tests may include a multipoint testing matching theselected access point and tag locations over multiple days. These testsmay demonstrate RF change over time and confirm that the coverage andaccuracy are consistent.

Another verification test may be a path loss test. Path loss may be ameasure of RF power loss (dBm or watts) over a specific distance. Byincreasing the path loss value in the service provider server 240, theservice provider server 240 is able to effectively calculate a highergain for the access points then they actually have. For example, a pathloss of 3.5 may be used for indoor use and 2.5 for outdoor use. Since RFenvironments may be different, path loss should be determined for eachunit, or facility, to determine best case accuracy. When taking multiplerecordings, the path loss of each recording may be incremented by 0.2until accuracy decreases. The recording with the best accuracy (therecording prior to the first decreased accuracy reading) should be usedas the path loss number.

Another verification test may include a single click verification test.The single click test may be used to confirm coverage and accuracy usingmore reference points than multipoint test, such as forty to fifty.Single click tests may take more time to complete compared tomulti-point recording tests. As such, the single click tests may not beperformed until the location of the access points is known with acertain accuracy, such as ninety-five percent. The single click testsmay take measurements by mapping individual test recordings together tocreate coverage and accuracy information. The tests may allowflexibility in reference point location since they do not require tagsto be placed prior to recording. The operator may find a physicalmeasurement location, input the reference point into the serviceprovider server 240 and record. For the best results of the single clicktesting, the operator 110 may start on the outside of edge of the testarea and take recordings every twenty to thirty feet in a clockwisepattern moving outside in. Once the ground level is completed, theoperator 110 may move to the next level and take recordings using theclockwise click pattern. This pattern may be continued until all levelsare completed.

Another verification test may be a walk around test. A walk around testmay be designed to mimic what operators and users of the real timelocation and gas exposure monitoring system may view when individualsare being tracked. Alternatively, one or more of the above-describedverification tests may be performed at step 870, and the results of thetests may be used at step 875 to determine whether the threshold is met.

FIG. 9 is a flowchart illustrating the generation of an access pointconfiguration in the system of FIG. 1, or other systems for relativepositioning of access points in a real time locating system. The stepsof FIG. 9 are described as being performed by the service providerserver 240. However, the steps may be performed by the processor of theservice provider server 240, or by any other hardware component of theservice provider server 240. Alternatively the steps may be performed byan external hardware component.

At step 905, the service provider server 240 may retrieve the layout ofthe facility or work area, such as from the data store 245.Alternatively or in addition, the service provider server 240 mayreceive the layout of the facility from the third party server 250, orfrom the operator 110 via the computing device 210. The layout mayinclude the architectural layout of the work area, including the numberof rooms, the size of the rooms, the number of floors, the size of thefloors, the height of the floors, and generally any other informationthat may be related to, or affected by the architectural layout of thework area. The layout may also include the infrastructure layout of thework area, including the location of power outlets, the location ofnetwork outlets, the location of power systems, the location and size ofany metallic or concrete objects, or generally any information relatedto, or affected by, the infrastructure layout. Alternatively or inaddition, the service provider server 240 may also receive one or morebusiness requirements associated with the system 100. For example, thebusiness requirements may include location accuracy, such as no lessthan fifty feet, wireless coverage, individual safety, systemreliability, cost and deployment timeframe. The layout of the work areamay include one or more architectural attributes, and one or moreinfrastructure attributes.

At step 910, the service provider server 240 may identify the floorlevels and the heights of the floor levels, such as identifying from thelayout. The floor levels and heights may be architectural attributes ofthe work area. At step 915, the service provider server 240 may identifythe high traffic areas of the work area, such as from the layout. Thehigh traffic areas may be walkways or other areas where large numbers ofpeople are expected. At step 920, the service provider server 240 maydetermine test locations of tags, such as radio frequency identificationtags, or the gas detection and locating devices 500A-B. The location ofthe test tags may be based on operator rounds and the high foot trafficareas of the work area, that is, areas where many individuals areexpected to be. The operator may input the actual location of the testtags to the service provider server 240, such that the actual locationscan be compared against the locations determined based on informationfrom the access points.

At step 925, the service provider server 240 may configure, catalog,and/or activate the test tags. The tags may be activated prior toperforming the testing and deactivated after performing the testing, inorder to conserve battery power. Each tag may be cataloged using anidentifier of the tag, such as a MAC address of the tag. Each tag may beactivated using a tag activator. For example, the tag activator may beconnected to the network 230, such as using an Ethernet cable. The tagmay be powered on and placed within close proximity of the tagactivator. The service provider server 240 may then activate the tag viathe tag activator. The tags may be configured with various settings,such as channel selection, transmission interval, motion sensoring, andany other settings which are supported by the tags.

At step 930, the service provider server 240 may identify areas of thework area which are proximal to electrical access and network access.For example, the service provider sever 240 may identify power outletsand network outlets in the layout. The areas proximal to the networkaccess may be beneficial for placing the access points such that theaccess points can be wired into the network. Likewise, the power outletsmay be used to connect the access points through a power over Ethernetconnection.

At step 935, the service provider server 240 may determine the initialnumber and placement of the access points. The initial number of accesspoints may be based on the overall square footage of the work area. Theaccess points may be positioned using a top-down approach. Elevatedaccess points may be used to provide coverage on high levels within thework area. The initial location of the access points may be based on thearchitectural and infrastructure attributes of the work area. Forexample, access points should not be placed within close proximity, suchas eight feet, to large concrete or metal obstructions identified in theattributes. The positioning of the access points may provideline-of-sight coverage for high traffic walkways. The positioning of theaccess points should include a mixture of elevations, such as ground,mid-level and high. The access points should be positioned relative toone another to form equilateral triangles or squares. Alternatively orin addition, the access points may form a circle or other polygons, suchas rhombus, trapezoid, parallelograms, or rectangles. The positioning ofthe access points should avoid lines, as they may provide less accuracy.The location and coverage of nearby access points should be included indetermining where to position an access point. The access points shouldbe positioned such that tags in the work area receive good signalcoverage from three or more access points. The access points should bepositioned such that the perimeter of the access points closelycoincides with the physical perimeter of the work area. The accesspoints should be positioned close to, or inside of, the unit batterylimits. If the target accuracy is fifty meters, the access points shouldnot be placed more than twenty-five meters from physical boundaries. Theaccess points should be positioned such that two access points in arenot placed in the same location at different elevations.

Alternatively or in addition, the location of the tags may bere-determined once the access point locations are determined. Forexample, the location of test tags may be based on various proximitiesto access points. The test tags may also be distributed throughout theunit's battery limits, and at various elevations.

At step 940, the service provider server 240 selects the first tag. Atstep 945, the service provider server 240 tests the coverage of the tag.At step 950, the service provider server 240 may determine whether thecoverage of the tag satisfies the coverage threshold. If the coverage ofthe tag does not meet the coverage threshold, the service providerserver 240 moves to step 955. At step 955, the location of the accesspoints are repositioned to improve the coverage of the tag. The serviceprovider server 240 then returns to step 945 and test the tag coverageagain.

If, at step 950, the service provider server 240 determines that thecoverage of the tag meets the coverage threshold, the service providerserver 240 moves to step 965. At step 965, the service provider server240 determines whether there are any additional tags to test. If, atstep 965, the service provider server 240 determines there areadditional tags to test, the service provider server 240 moves to step970. At step 970, the service provider server 240 selects the next tagand moves to step 945 to test the next tag. If, at step 965, the serviceprovider server 240 determines that there are no additional tags totest, the service provider server 240 moves to step 975.

Alternatively or in addition, the service provider server 240 mayreposition the access points as a whole. For example, the location ofeach access point may be considered a part of a vector, such that thelocation of each access point has some effect over the accuracy of theother access points. Thus, moving one access point may increase, ordecrease, the accuracy of other access points.

At 975, the service provider server 240 selects the first access point.At step 980, the service provider server 240 determines whether theaccess point meets the location accuracy threshold. For example, thethreshold may indicate that the location accuracy should be an averageof twenty meters or less. The location accuracy may be determined bycomparing the actual location of the tags inputted by the operator withthe location of the tags determined from information received from theaccess points.

If, at step 980, the service provider server 240 determines that theaccess point meets the accuracy threshold, the service provider server240 moves to step 992. At step 992, the service provider server 240determines whether there are additional access points. If, at step 992,the service provider server 240 determines that there are additionalaccess points, the service provider server 240 moves to step 990. Atstep 990, the service provider server 240 selects the next access pointand then returns to step 980.

If, at step 980, the service provider server 240 determines that theaccess point does not meet the accuracy threshold, the service providerserver 240 moves to step 985. At step 985, the service provider server240 may reposition the access point and return to step 980 to re-testthe location accuracy of the access point. If, at step 992, the serviceprovider server 240 determines that there are no additional accesspoints, the service provider server 240 moves to step 995. At step 955,the service provider server 240 provides the access point configuration,such as to the operator.

FIG. 10 is a flowchart illustrating the detection of gas by a gasdetection and locating device in the system of FIG. 1, or other systemsfor relative positioning of access points in a real time locatingsystem. The steps of FIG. 10 are described as being performed by a gasdetection and locating device 500A, 500B. However, the steps may beperformed by the processor of the gas detection and locating device500A, 500B, or by any other hardware component of the gas detection andlocating device 500A, 500B. Alternatively the steps may be performed byan external hardware component.

At step 1010, the gas detection and locating device 500A may detect ahazardous gas in the vicinity of the user A 120A. For example, the gassensor 524 of the gas detection and locating device 500A may detect ahazardous gas, such as hydrogen sulfide. At step 1020, the gas detectionand locating device 500A may determine whether the level of hazardousgas meets an alarm threshold. The alarm threshold may be identified bythe operator 110 and may be stored in the data store 245. If, at step1020, the gas detection and locating device 500A determines that thelevel of gas detected does not meet the alarm threshold, the gasdetection and locating device 500A moves to step 1030. At step 1030, thegas detection and locating device 500A does not transmit an alarm as thelevel of gas detected does not meet the threshold level.

If, at step 1020, the gas detection and locating device 500A determinesthat the level of gas meets the alarm threshold, the gas detection andlocating device 500A moves to step 1040. At step 1040, the gas detectionand location device 500A activates a local alarm. The local alarm maycause the gas detection and locating device 500A to vibrate, flash, playa sound, or otherwise attract the attention of the user A 120A. At step1050, the gas detection and locating device 500A transmits an alarm tothe service provider server 240. The alarm data may include the amountof gas the user A 120A has been exposed to, and the location of the userA 120A. For example, the gas sensor 524 may communicate the amount ofgas exposure to the location device 510. The location device mayretrieve the location of the user A 120A from the location processor514, if available. The location device 510 may then transmit the amountof gas exposure and the location of the user A 120A to the serviceprovider server 240. Alternatively or in addition, if the location ofthe user A 120A cannot be determined by the location device 510, theservice provider server 240 may retrieve the location of the user A 120Afrom the wireless location server 260. The service provider server 240may receive the alarm data item and may perform one or more alarmhandling actions based on the alarm data. The actions performed by theservice provider server 240 are discussed in more detail in FIG. 13below.

Alternatively or in addition, the gas detection and locating device 500Amay communicate the amount of gas exposure and the location of the userA 120A to the service provider server 240 on a periodic basis, such asevery minute. The service provider server 240 may analyze the amount ofgas exposure and location of the user A 120A to determine whether theuser A 120A has been exposed to harmful levels of gas. If the serviceprovider server 240 determines that the user A 120A has been exposed toharmful levels of gas, the service provider server 240 may communicatean alarm to the gas detection and locating device 500A, and may performthe one or more alarm handling actions. The gas detection and locatingdevice 500A may activate the local alarm. By offloading the processingof the gas exposure data to the service provider server 240, the sizeand weight of the gas detection and locating device 500A may be reduced.

FIG. 11 is a flowchart illustrating a panic button activation by a gasdetection and locating device in the system of FIG. 1, or other systemsfor relative positioning of access points in a real time locatingsystem. The steps of FIG. 11 are described as being performed by a gasdetection and locating device 500A, 500B. However, the steps may beperformed by the processor of the gas detection and locating device500A, 500B, or by any other hardware component of the gas detection andlocating device 500A, 500B. Alternatively the steps may be performed byan external hardware component.

At step 1110, the gas detection and locating device 500A may detect thatthe panic button on the outside of the casing 505 of the gas detectionand locating device 500A has been activated, such as when a user A 120Apresses the panic button. At step 1120, the location device 510 maytransmit an alarm to the service provider server 240. The alarm dataitem may include the current gas exposure of the user A 120A, asdetected by the gas sensor 524, and the current location of the user A120A. The service provider server 240 may receive the alarm data itemand may perform one or more alarm response actions based on the receivedalarm data item. The alarm response actions are discussed in more detailin FIG. 13 below.

FIG. 12 is a flowchart illustrating a lack of motion detection by a gasdetection and locating device in the system of FIG. 1, or other systemsfor relative positioning of access points in a real time locatingsystem. The steps of FIG. 12 are described as being performed by a gasdetection and locating device 500A, 500B. However, the steps may beperformed by the processor of the gas detection and locating device500A, 500B, or by any other hardware component of the gas detection andlocating device 500A, 500B. Alternatively the steps may be performed byan external hardware component.

At step 1210, the gas detection and locating device 500A may detect alack of motion by the user A 120A. For example, the gas detection andlocating device 500A may detect that the user A 120A has not movedlocations for a period of time. The period of time may be configured bythe operator 110, and may be any period of time, such as one minute. Theoperator 110 may configure different periods of time for each user120A-N, such as based on the age of the users 120A-N, or otherdemographic information of the users 120A-N. Alternatively or inaddition, the period of time may be based on the current location of auser A 120A. For example, if the user A 120A is in a cafeteria, then theuser A 120A may be expected to be stationary for an extended period oftime. Thus, the period of time may be longer when the user A 120A islocated in a cafeteria. However, when the user A 120A is located withina hallway, the user A 120A may be expected to be continuously moving,and therefore the period of time may be shorter. Alternatively or inaddition, the gas detecting and location device 500A may include anaccelerometer. The accelerometer may be able to detect motion of theuser A 120A. Thus, if the accelerometer does not detect any motion for aperiod of time, a lack of motion alarm may be initiated.

Alternatively or in addition, the service provider server 240 maymonitor the movement of the user A 120A and may detect that the user A120A has not moved for the period of time. In this instance, the serviceprovider server 240 may communicate a lack of motion alarm to the gasdetection and locating device 500A, which may cause the gas detectionand locating device 500A to move to step 1220.

At step 1220, the gas detection and locating device 500A may activate alocal alarm. As mentioned above, the local alarm may cause the gasdetection and locating device 500A to vibrate, light up, play a sound,or otherwise attract the attention of the user A 120A. At step 1230, thegas detection and locating device 500A determines whether the user A120A responded to the local alarm within a response time. For example,the user A 120A may press a button on the casing 505 of the gasdetection and locating device 500A to acknowledge the alarm and verifythat there is not a problem. Alternatively or in addition, the user A120A may press another button on the casing 505 of the gas detection andlocating device to indicate that there is a problem. The response timemay be configurable and may be determined by the operator 110. Theresponse time may be any period of time, such as five seconds.

If, at step 1220, the gas detection and locating device 500A determinesthat the user A 120A presses the button indicating that there is noproblem within the response time, the gas detection and locating device500A moves to step 1240. At step 1240, the gas detection and locatingdevice 500A closes the alarm. If the alarm was initiated by the serviceprovider server 240, the gas detection and locating device 500Atransmits an indication that the alarm should be closed to the serviceprovider server 240.

If, at step 1220, the gas detection and locating device 500A determinesthat the user A 120A did not press the button within the response time,or the user A 120A pressed the button indicating that there is aproblem, the gas detection and locating device 500A moves to step 1250.At step 1250, the gas detection and locating device transmits an alarmto the service provider server 240. The alarm data may include theamount of gas the user A 120A was exposed to and the current location ofthe user A 120A. The service provider server 240 may receive the alarmdata and may perform one or more alarm response actions based on thealarm data. The alarm response actions performed by the service providerserver 240 are discussed in more detail in FIG. 13 below.

FIG. 13 is a flowchart illustrating an alarm received from a gasdetection and locating device in the system of FIG. 1, or other systemsfor relative positioning of access points in a real time locatingsystem. The steps of FIG. 13 are described as being performed by theservice provider server 240. However, the steps may be performed by theprocessor of the service provider server 240, or by any other hardwarecomponent of the service provider server 240. Alternatively the stepsmay be performed by an external hardware component.

At step 1310, the service provider server 240 may receive alarm data,such as from one of the gas detection and locating devices 220A-N, suchas the gas detection and locating device A 220A. The alarm data may havebeen transmitted to the service provider server 240 in response to thepanic button being pressed, the user A 120A being exposed to anunhealthy level of hazardous gas, the user A 120A not responding to alack of motion alarm within the response period, or generally any otheralarm related to the activity of the user A 120A in the work area.

At step 1320, the service provider server 240 may identify theindividual. For example, the alarm data communicated to the serviceprovider server 240 may include information identifying the user A 120A,or identifying the gas detection and locating device A 220A. If theinformation identifies the gas detection and locating device A 220A, theservice provider server 240 may retrieve data from the data store 245 todetermine the user A 120A associated with the gas detection and locatingdevice A 220A.

At step 1330, the service provider server 240 may initiate communicationwith the user A 120A in the field. For example, the service providerserver 240 may automatically attempt to connect the operator 110 to thewalkie-talkie of the user A 120A, or the mobile phone of the user A120A. The service provider server 240 may retrieve the walkie-talkieand/or mobile phone information of the user A 120A from the data store245. The operator may inform the user A 120A that they have been exposedto harmful amounts of hazardous gas and should evacuate the contaminatedarea immediately. Alternatively or in addition, the service providerserver 240 may utilize an interactive voice response system (IVR). TheIVR may automatically connect to the walkie-talkie or mobile device ofthe user A 120A and may play a message to the user A 120A instructingthe user A 120A to evacuate the area immediately.

The service provider server 240 may identify the contaminated area basedon the amount of gas the other users 120B-N have been exposed to and thelocation of the other users 120B-N within the work area. Alternativelyor in addition, the service provider server 240 may receive gas levelinformation from one or more stationary gas sensors located throughoutthe work area. If the service provider server 240 cannot isolate acontaminated area, the service provider server 240 may assume that theentire indoor work area is contaminated.

At step 1340, the service provider server 240 may identify the locationof the user A 120A in the work area. The location of the user A 120A inthe work area may be determined based on the location informationreceived from the gas detection and locating device 500A and/or thenetwork infrastructure, such as the wireless location server 260. Atstep 1350, the service provider server 240 may communicate an alarm,with the location of the user A 120A within the work area, to one ormore operators located within the vicinity of the user A 120A. Theoperators may use mobile devices, such as an APPLE IPHONE, to view thealarm data and view the location of the user A 120A relative to eachoperator. For example, the mobile device may include a map of the workarea, which may display the current location of the operator and thelocation of the user A 120A. The operators may attempt to reach the userA 120A and evacuate the user A 120A from the area contaminated with thehazardous gas.

Alternatively or in addition, the service provider server 240 maycommunicate the location of other users 120B-N who also may need to beevacuated from the contaminated area. Although the amount of gasexposure of the users 120A-N may be below the alarm threshold, theservice provider server 240 may be able to predict an expected amount ofgas exposure of the users 120B-N over a period of time based on the gasexposure of the user A120A. If the service provider server 240 predictsan amount of gas exposure which meets the alarm threshold for the users120B-N, the users 120B-N may also be evacuated from the contaminatedarea.

At step 1360, the service provider server 240 may receive notificationthat the user A 120A has been located by one of the operators. Forexample, an operator may locate the user A 120A and may activate abutton on their mobile device to indicate that the user A 120A has beenlocated. Alternatively or in addition, an operator may initiate acommunication with the operator 110 and may inform the operator 110 thatthe user A 120 has been located. The operator 110 may then update theservice provider server 240 via the computing device 210.

At step 1365, the service provider server 240 may determine whetheremergency responders are required. Emergency responders may includemedical personnel, hazardous material (HAZMAT) personnel, securitypersonnel, fire department personnel, or generally any emergencyresponders. In one example, the operator 110, or one of the operatorswho locates the user A 120A, may communicate an indication to theservice provider server 240 that one or more types of emergencypersonnel are required. Alternatively or in addition, the serviceprovider server 240 may automatically identify one or more emergencyresponders required using data received from the gas detection andlocating devices 220A-N of the users 120A-N, stationary gas detectiondevices, fire sensors, and/or any additional sensors the serviceprovider server 240 has access to. For example, the service providerserver 240 may determine that fire department personnel are required ifone or more fire alarms were triggered. Alternatively or in addition,the service provider server 240 may determine that hazardous materialpersonnel are required if the gas contamination meets a threshold

If, at step 1365, the service provider server 240 determines that one ormore emergency personnel are required, the service provider server 240moves to step 1370. At step 1370, the service provider server 240initiates communication with a communication device of the identifiedone or more emergency personnel, such as via a voice or datacommunication. If, at step 1365, the service provider server 240determines that no emergency personnel are required, then the serviceprovider server 240 moves to step 1380. At step 1380, the serviceprovider server 240 closes the alarm. For example, the operators wholocated the user A 120A may have evacuated the user A 120A from thecontaminated area.

FIG. 14 is a flowchart illustrating high risk area prediction in thesystem of FIG. 1, or other systems for relative positioning of accesspoints in a real time locating system. The steps of FIG. 14 aredescribed as being performed by the service provider server 240.However, the steps may be performed by the processor of the serviceprovider server 240, or by any other hardware component of the serviceprovider server 240. Alternatively the steps may be performed by anexternal hardware component.

At step 1410, the service provider server 240 may receive sensor data,such as a hazardous gas level, from multiple sensors. The sensors mayinclude sensors within the badges 220A-N, and/or stationary wirelesssensors 375. At step 1420, the service provider server 240 may analyzethe sensor data. For example, the service provider server 240 maydetermine whether the level of hazardous gas is increasing or decreasingfor each sensor, and may determine the rate of change of the level ofhazardous gas for each sensor. At step 1425, the service provider server240 may determine whether there has been an increase in the level ofhazardous gas for one or more sensors. If, at step 1425, the serviceprovider server 240 determines that there has not been an increase inany of the gas levels, the service provider server 240 moves to step1440. At step 1440, the service provider server 240 determines there areno predicted high risk areas.

If, at step 1425, the service provider server 240 determines that thereis an increase in the gas levels detected by one or more of the sensors,the service provider server 240 moves to step 1430. At step 1430, theservice provider server 240 determines the rate of change in thedetected gas levels, such as based on the last several measurementsreceived from the sensors. For example, if the gas levels arecommunicated from the sensors to the service provider server 240 everyminute, the service provider server 240 may determine the rate of changeover the last five minutes. At step 1450, the service provider server240 determines whether the rate of change of the gas levels indicatesthat dangerous levels of the hazardous gas may be imminent. For example,the service provider server 240 may identify a dangerous level of thehazardous gas and may determine, based on the rate of change in gaslevels, whether the levels of the hazardous gas may reach the dangerouslevel.

If, at step 1450, the service provider server 240 determines that therate of change of the gas levels does not indicate that dangerous levelsof the gas are imminent, the service provider server 240 moves to step1440. At step 1440, the service provider server 240 determines there areno predicted high risk areas. If, at step 1450, the service providerserver 240 determines the rate of change of the hazardous gas level isindicative of imminent dangerous levels of the hazardous gas, theservice provider server 240 moves to step 1455. At step 1455, theservice provider server 240 determines whether the sensors in proximityto the imminent dangerous levels of the hazardous gas are locatedindoors or outdoors.

If, at step 1455, the service provider server 240 determines the sensorsare located outdoors, the service provider server 240 moves to step1470. At step 1470, the service provider server 240 determines apredicted flow of the hazardous gas based on data describing the currentdirection and rate, or strength, of the wind. For example, if the windis blowing in a southerly direction, then the gas may be likely to moveto the south. Alternatively or in addition, the service provider server240 may utilize historical sensor readings to determine how quickly thedirection and rate of the wind may result in a dissipation of thehazardous gas.

If, at step 1455 the service provider server 240 determines that thesensors are located indoors, the service provider server 240 moves tostep 1460. At step 1460, the service provider server 240 determines apredicted flow, or movement, of the hazardous gas based on historicalsensor readings which are indicative of the circulation of the airindoors. For example, the historical progression of a gas through thesensor network can be analyzed by reviewing historical sensormeasurements. The service provider server 240 may generate a gas flowmodel based on the historical sensor data and may use the gas flow modelto predict the movement of the hazardous gas.

At step 1480, the service provider server 240 may identify the users120A-N who are located in areas which are predicted to have high levelsof the hazardous gas in the near future, such as within the next fiveminutes, the next ten minutes, or generally any time interval. The users120A-N may be identified based on the badges 220A-N of the users 120A-N.At step 1490, the service provider server 240 may transmit apre-emptive, or pro-active, alarm to the badges 220A-N of the users120A-N who are located in the areas which are predicted to have highlevels of hazardous gas in the near future. The users 120A-N may receivethe alerts and may evacuate the high risk areas.

Alternatively or in addition, the service provider server 240 may usethe data retrieved from the sensors and the gas flow predictive model todetermine which vents to open and/or close, such as to contain thehazardous gas. For example, the service provider server 240 may shut oneor more vents to isolate the hazardous gas within a confined area, suchas an evacuated room. Alternatively, the service provider server 240 mayopen vents to provide uncontaminated air to an area with high levels ofthe hazardous gas.

FIG. 15 is a screenshot of a user interface 1500 for viewing accesspoint coverage of a facility in the system of FIG. 1, or other systemsfor relative positioning of access points in a real time locatingsystem. The user interface 1500 may include a map 1510 and one or morecoverage indicators 1515. The coverage indicators 1515 may indicate thelevel of coverage at each area of the map 1510. The user interface 1500may display the coverage of a single access point 360. Alternatively orin addition, the user interface may simultaneously display the coverageof multiple access points 360. The user interface 1500 displaying thecoverage of an access point 360 may also be referred to as the heatmapof the access point 360.

In operation, the user interface 1500 may be provided to the operator110 via the computing device 210. The operator 110 may use the userinterface 1500 to view the coverage of one or more access points 360 inthe system 100. If the user interface 1500 indicates that the coverageof the access points 360 does not satisfy the coverage threshold, thenthe access points 360 may be re-positioned with the facility.

FIG. 16 is a screenshot of a user interface 1600 for viewing accesspoint coverage of individual access points 360 in the system of FIG. 1,or other systems for relative positioning of access points in a realtime locating system. The user interface 1600 may include a map 1610 anda coverage key 1620. The map 1610 may include one or more tags 1612 andone or more access points 1614. The tags 1612 may represent the locationof the test tags and the access points 1614 may represent the locationof the MAMALs. The tags 1612 and/or access points 1614 may be surroundedby one or more colors. The colors may indicate the level of coverage atthe tag 1612 and/or access point 1614. The coverage key 1620 may providea mapping between the colors and the coverage values.

In operation, the user interface 1600 may be provided to the operator110 via the computing device 210. The operator 110 may use the userinterface 1600 to view the coverage of multiple access points 360 in thesystem 100. If the user interface 1600 indicates that the coverage ofthe access points 360 does not satisfy the coverage threshold, then theaccess points 360 may be re-positioned with the facility.

FIG. 17 is a screenshot of a user interface for viewing access pointlocating accuracy in the system of FIG. 1, or other systems for relativepositioning of access points in a real time locating system. The userinterface 1700 may include a map 1710 and an accuracy key 1720. The map1710 may include one or more accuracy level indicators 1715, which maybe represented by various colored shading on the map 1710. The colors ofthe accuracy indicators 1715 may indicate the level of accuracy atvarious locations on the map 1710. The accuracy key 1720 may provide amapping between the colors and the accuracy levels.

In operation, the user interface 1700 may be provided to the operator110 via the computing device 210. The operator 110 may use the userinterface 1700 to view the coverage of multiple access points 360 in thesystem 100. If the user interface 1700 indicates that the accuracy levelof the access points 360 does not satisfy the accuracy threshold, thenthe access points 360 may be re-positioned with the facility.

FIG. 18 is a screenshot of a user interface 1800 displaying a placementanalysis report 1805 in the system of FIG. 1, or other systems forrelative positioning of access points in a real time locating system.The placement analysis report 1805 may include one or more sectionscontaining information relating to the positioning of one or more accesspoints. The sections of the placement analysis report may include a testnumber section 1810, a recording title section 1820, a change section1830, an access point placement section 1840, an individual coveragesection 1850, an accuracy section 1860, a tags not covered section 1870,a results description 1880, and an overall coverage and accuracy mapsection 1890.

The test number section 1810 may display the number of the RF test underreview. For example, the service provider server 240 may assign a uniquenumber to each RF test that is performed. The recording title section1820 may display the name of the folder where the recording informationis stored. The change section 1830 may display a description of anaccess point 360 that moved between the last test and the current test.For example, the change section 1830 may indicate that access point 1moved to an elevation of ten feet. The access point placement section1840 may list each of the access points' relative location on the map.For example, the access point placement section 1840 may list accesspoint 1 as being in the northwest corner by the boiler and access point2 in the southwest corner on the brick building. The individual accesspoint coverage section 1850 may list if each access point's coverage iswithin the area. For example, the individual access point coveragesection 1850 may include one or more descriptors indicating the qualityof the coverage, such as “great,”, “good,” “ok”, or “bad.” The “great”descriptor may indicate that the majority of the access points 360 havecoverage of at least −65 dBM and at least fifty percent of the work areais covered. The “good” descriptor may indicate that the majority ofaccess points 360 have coverage of at least −75 dBM and at least fiftypercent of the work area is covered. The “ok” descriptor may indicatethat the majority of access points 360 have coverage of at least −75 dBMand at least twenty-five percent of the work area is covered. The “bad”descriptor may indicate that the majority of access points 360 havecoverage of at least −85 dBM and at least twenty-five percent of thework area is covered. The accuracy section 1860 may display themeasurement of the overall access point accuracy at 90% RE. The tags notcovered section 1870 may display the number of tags not covered by atleast three access points 360 at −75 dBm or greater. The results section1880 may display a recommendation of the RF test's placement of accesspoints and the coverage and accuracy interpretation. The overallcoverage and accuracy maps section 1890 may display screenshots of thecoverage and accuracy maps, such as those displayed in FIGS. 15-17above.

FIG. 19 is a screenshot of a user interface 1900 for monitoring thelocation and gas exposure level of users in the system of FIG. 1, orother systems for relative positioning of access points in a real timelocating system. The user interface 1900 may include a map 1910 and oneor more user identifiers 1920. The user identifiers 1920 may indicatethe location of the users 120A-N in the workplace. Alternatively or inaddition, the user identifiers 1920 may also display the amount of gaseach user 120A-N has been exposed to. The user identifiers may changecolors based on the amount of gas each user 120A-N has been exposed to.For example, if a user A 120A has been exposed to small amounts of gas,the user identifier 1920 of the user A120A may be green. Alternatively,if a user B 120B has been exposed to large amounts of gas, the useridentifier 1920 of the user B 120B may be red. The user identifier 1920of a user B 120B who has been exposed to large amounts of gas may alsoflash or otherwise be displayed visually distinct from the other useridentifiers 1920.

In operation, the user interface 1900 may be provided to the operator110 via the computing device 210. The operator 110 may use the userinterface 1900 to monitor the location and amount of gas exposure of theusers 120A-N. The operator 110 may use the user interface 1500 toinitiate a manual alarm for one or more users 120A-N. The alarm may betransmitted to the gas detection and locating device 220A-N of the users120A-N by the service provider server 240. For example, if the operator110 identifies a reason the users 120A-N should be evacuated, such as atornado or other weather related issue, the operator 110 may initiate amanual alarm. Alternatively or in addition, the service provider server240 may be in communication with one or more third party servers 250which provide severe weather alerts. The service provider server 240 mayautomatically initiate an alarm for all of the users 120A-N if theservice provider server 240 receives indication of imminent severeweather, such as a tornado or flood.

Alternatively or in addition, when an alarm is received, the userinterface 1900 may be provided to a mobile device of one or moreoperators located within the vicinity of the user A 120A associated withthe alarm. The operators may use the user interface 1900 to locate theuser A 120A. Alternatively or in addition, the user interface 1900 maydisplay directions to each operator to locate the user A 120A based onthe current location of each operator. Alternatively or in addition, themobile device of each operator may provide audible directions to eachoperator.

Alternatively or in addition, if a “man down” alarm is received for auser A 120A, the user interface 1900 may be configured to quickly openand zoom to the location of the user A 120A. Alternatively or inaddition, the user interface 1900 may be used to view a simulation ofthe effect of a gas leak, or gas cloud, on the work area. The userinterface 1900 may also include time on tools calculation, which mayprovide a maintenance productivity calculation.

FIG. 20 is a screenshot of a user interface 2000 for monitoring gasexposure levels in the system of FIG. 1, or other systems for relativepositioning of access points in a real time locating system. The userinterface 2000 may include a selection interface 2010 and a gas leveldisplay 2020. The gas level display 2020 may include one or more gassensors 2025. The selection interface 2010 may allow the user A 120A toselect one or more options, or filters, which may affect the format ordisplay of the gas levels on the gas level display 2020. The gas leveldisplay 2020 may display the location of the gas sensors 2025 and thelevels of gas detected by the sensors. The sensors may be standalonesensors 375, or may be badges 220A-N. Since the badges 220A-N alsocontain location data, the gas levels displayed on the gas level display2020 may be updated as the users 120A-N move throughout the workplace.

FIG. 21 is a screenshot of a user interface 2100 for monitoring thelocation and gas exposure level of users using a positioning system inthe system of FIG. 1, or other systems for relative positioning ofaccess points in a real time locating system. The user interface 2100may include a map display 2110, a user A 120A, and a workplace 2130. Theuser interface 2100 may be provided to the operator 110, such as throughthe computing device 210.

In operation, the operator 110 may use the map display 2110 to view thelocation of the users 120A-N outside of the workplace 2130. The users120A-N may be located remotely from the workplace 2130, or may belocated in an area of the workplace outside of the sensor network. Theservice provider server 240 may utilize positioning data, such as GPSdata, received from the gas detection and locating devices 220A-N toidentify the geographic location of each of the users 120A-N and assets.Alternatively or in addition, if the user A 120A is located out of rangeof the positioning system satellites, the service provider server 240may receive location information from the wireless location server 260,from third party programs or servers, such as GOGGLE LATITUDE™, or fromcellular phone towers, such as by triangulating signals of cellularphone towers in communication with the badge 220A of the user A 120A.The map display 2110 may also include one or more metrics related to theuser A 120A, such as level of gas exposure, location, biometricinformation, such as heart rate or blood pressure, or generally anyother information which may describe the selected user A 120A or asset.Alternatively or in addition, the user interface 2100 may be used formustering either thru integrating Lenel or through Exciter use.

FIG. 22 illustrates a general computer system 2200, which may representa service provider server 240, a gas detection and location device220A-N, 500A, 500B, a computing device 210, a wireless location server260, a third party server 250, a MAMAL 600, 700, or any of the othercomputing devices referenced herein. The computer system 2200 mayinclude a set of instructions 2224 that may be executed to cause thecomputer system 2200 to perform any one or more of the methods orcomputer based functions disclosed herein. The computer system 2200 mayoperate as a standalone device or may be connected, e.g., using anetwork, to other computer systems or peripheral devices.

In a networked deployment, the computer system may operate in thecapacity of a server or as a client user computer in a server-clientuser network environment, or as a peer computer system in a peer-to-peer(or distributed) network environment. The computer system 2200 may alsobe implemented as or incorporated into various devices, such as apersonal computer (PC), a tablet PC, a set-top box (STB), a personaldigital assistant (PDA), a mobile device, a palmtop computer, a laptopcomputer, a desktop computer, a communications device, a wirelesstelephone, a land-line telephone, a control system, a camera, a scanner,a facsimile machine, a printer, a pager, a personal trusted device, aweb appliance, a network router, switch or bridge, or any other machinecapable of executing a set of instructions 2224 (sequential orotherwise) that specify actions to be taken by that machine. In aparticular embodiment, the computer system 2200 may be implemented usingelectronic devices that provide voice, video or data communication.Further, while a single computer system 2200 may be illustrated, theterm “system” shall also be taken to include any collection of systemsor sub-systems that individually or jointly execute a set, or multiplesets, of instructions to perform one or more computer functions.

As illustrated in FIG. 22, the computer system 2200 may include aprocessor 2202, such as, a central processing unit (CPU), a graphicsprocessing unit (GPU), or both. The processor 2202 may be a component ina variety of systems. For example, the processor 2202 may be part of astandard personal computer or a workstation. The processor 2202 may beone or more general processors, digital signal processors, applicationspecific integrated circuits, field programmable gate arrays, servers,networks, digital circuits, analog circuits, combinations thereof, orother now known or later developed devices for analyzing and processingdata. The processor 2202 may implement a software program, such as codegenerated manually (i.e., programmed).

The computer system 2200 may include a memory 2204 that can communicatevia a bus 2208. The memory 2204 may be a main memory, a static memory,or a dynamic memory. The memory 2204 may include, but may not be limitedto computer readable storage media such as various types of volatile andnon-volatile storage media, including but not limited to random accessmemory, read-only memory, programmable read-only memory, electricallyprogrammable read-only memory, electrically erasable read-only memory,flash memory, magnetic tape or disk, optical media and the like. In onecase, the memory 2204 may include a cache or random access memory forthe processor 2202. Alternatively or in addition, the memory 2204 may beseparate from the processor 2202, such as a cache memory of a processor,the system memory, or other memory. The memory 2204 may be an externalstorage device or database for storing data. Examples may include a harddrive, compact disc (“CD”), digital video disc (“DVD”), memory card,memory stick, floppy disc, universal serial bus (“USB”) memory device,or any other device operative to store data. The memory 2204 may beoperable to store instructions 2224 executable by the processor 2202.The functions, acts or tasks illustrated in the figures or describedherein may be performed by the programmed processor 2202 executing theinstructions 2224 stored in the memory 2204. The functions, acts ortasks may be independent of the particular type of instructions set,storage media, processor or processing strategy and may be performed bysoftware, hardware, integrated circuits, firm-ware, micro-code and thelike, operating alone or in combination. Likewise, processing strategiesmay include multiprocessing, multitasking, parallel processing and thelike.

The computer system 2200 may further include a display 2214, such as aliquid crystal display (LCD), an organic light emitting diode (OLED), aflat panel display, a solid state display, a cathode ray tube (CRT), aprojector, a printer or other now known or later developed displaydevice for outputting determined information. The display 2214 may actas an interface for the user to see the functioning of the processor2202, or specifically as an interface with the software stored in thememory 2204 or in the drive unit 2206.

Additionally, the computer system 2200 may include an input device 2212configured to allow a user to interact with any of the components ofsystem 2200. The input device 2212 may be a number pad, a keyboard, or acursor control device, such as a mouse, or a joystick, touch screendisplay, remote control or any other device operative to interact withthe system 2200.

The computer system 2200 may also include a disk or optical drive unit2206. The disk drive unit 2206 may include a computer-readable medium2222 in which one or more sets of instructions 2224, e.g. software, canbe embedded. Further, the instructions 2224 may perform one or more ofthe methods or logic as described herein. The instructions 2224 mayreside completely, or at least partially, within the memory 2204 and/orwithin the processor 2202 during execution by the computer system 2200.The memory 2204 and the processor 2202 also may includecomputer-readable media as discussed above.

The present disclosure contemplates a computer-readable medium 2222 thatincludes instructions 2224 or receives and executes instructions 2224responsive to a propagated signal; so that a device connected to anetwork 235 may communicate voice, video, audio, images or any otherdata over the network 235. Further, the instructions 2224 may betransmitted or received over the network 235 via a communicationinterface 2218. The communication interface 2218 may be a part of theprocessor 2202 or may be a separate component. The communicationinterface 2218 may be created in software or may be a physicalconnection in hardware. The communication interface 2218 may beconfigured to connect with a network 235, external media, the display2214, or any other components in system 2200, or combinations thereof.The connection with the network 235 may be a physical connection, suchas a wired Ethernet connection or may be established wirelessly asdiscussed below. Likewise, the additional connections with othercomponents of the system 2200 may be physical connections or may beestablished wirelessly. In the case of a service provider server 240,the service provider server may communicate with users 120A-N throughthe communication interface 2218.

The network 235 may include wired networks, wireless networks, orcombinations thereof. The wireless network may be a cellular telephonenetwork, an 802.11, 802.16, 802.20, or WiMax network. Further, thenetwork 235 may be a public network, such as the Internet, a privatenetwork, such as an intranet, or combinations thereof, and may utilize avariety of networking protocols now available or later developedincluding, but not limited to TCP/IP based networking protocols.

The computer-readable medium 2222 may be a single medium, or thecomputer-readable medium 2222 may be a single medium or multiple media,such as a centralized or distributed database, and/or associated cachesand servers that store one or more sets of instructions. The term“computer-readable medium” may also include any medium that may becapable of storing, encoding or carrying a set of instructions forexecution by a processor or that may cause a computer system to performany one or more of the methods or operations disclosed herein.

The computer-readable medium 2222 may include a solid-state memory suchas a memory card or other package that houses one or more non-volatileread-only memories. The computer-readable medium 2222 also may be arandom access memory or other volatile re-writable memory. Additionally,the computer-readable medium 2222 may include a magneto-optical oroptical medium, such as a disk or tapes or other storage device tocapture carrier wave signals such as a signal communicated over atransmission medium. A digital file attachment to an e-mail or otherself-contained information archive or set of archives may be considereda distribution medium that may be a tangible storage medium.Accordingly, the disclosure may be considered to include any one or moreof a computer-readable medium or a distribution medium and otherequivalents and successor media, in which data or instructions may bestored.

Alternatively or in addition, dedicated hardware implementations, suchas application specific integrated circuits, programmable logic arraysand other hardware devices, may be constructed to implement one or moreof the methods described herein. Applications that may include theapparatus and systems of various embodiments may broadly include avariety of electronic and computer systems. One or more embodimentsdescribed herein may implement functions using two or more specificinterconnected hardware modules or devices with related control and datasignals that may be communicated between and through the modules, or asportions of an application-specific integrated circuit. Accordingly, thepresent system may encompass software, firmware, and hardwareimplementations.

The methods described herein may be implemented by software programsexecutable by a computer system. Further, implementations may includedistributed processing, component/object distributed processing, andparallel processing. Alternatively or in addition, virtual computersystem processing maybe constructed to implement one or more of themethods or functionality as described herein.

Although components and functions are described that may be implementedin particular embodiments with reference to particular standards andprotocols, the components and functions are not limited to suchstandards and protocols. For example, standards for Internet and otherpacket switched network transmission (e.g., TCP/IP, UDP/IP, HTML, HTTP)represent examples of the state of the art. Such standards areperiodically superseded by faster or more efficient equivalents havingessentially the same functions. Accordingly, replacement standards andprotocols having the same or similar functions as those disclosed hereinare considered equivalents thereof.

The illustrations described herein are intended to provide a generalunderstanding of the structure of various embodiments. The illustrationsare not intended to serve as a complete description of all of theelements and features of apparatus, processors, and systems that utilizethe structures or methods described herein. Many other embodiments maybe apparent to those of skill in the art upon reviewing the disclosure.Other embodiments may be utilized and derived from the disclosure, suchthat structural and logical substitutions and changes may be madewithout departing from the scope of the disclosure. Additionally, theillustrations are merely representational and may not be drawn to scale.Certain proportions within the illustrations may be exaggerated, whileother proportions may be minimized. Accordingly, the disclosure and thefigures are to be regarded as illustrative rather than restrictive.

The above disclosed subject matter is to be considered illustrative, andnot restrictive, and the appended claims are intended to cover all suchmodifications, enhancements, and other embodiments, which fall withinthe true spirit and scope of the description. Thus, to the maximumextent allowed by law, the scope is to be determined by the broadestpermissible interpretation of the following claims and theirequivalents, and shall not be restricted or limited by the foregoingdetailed description.

1. A method for relative positioning of access points in a real timelocating system, the method comprising: receiving layout information ofa work area, wherein the layout information comprises architecturalattributes and infrastructure attributes of the work area; determining anumber of a plurality of access points to position in the work area,wherein the determining is based on the architectural attributes of thework area; determining a placement in the work area of at least one testradio frequency tag, wherein the determining is based on theinfrastructure attributes of the work area; determining, by a processor,a positioning of the plurality of access points in the work area,wherein the positioning substantially maximizes a coverage and anaccuracy of locating the at least one test radio frequency tag in thework area; and determine a repositioning of at least one of theplurality of access points when the coverage and accuracy do not satisfya threshold, and providing a graphical representation of the positioningof each of the plurality of access points in the work area, relative toone another, when the coverage and the accuracy satisfy the threshold.2. The method of claim 1 wherein the architectural attributes compriseat least one of a number of levels of the work area, a height of alevel, an average amount of foot traffic in portions of the work area, awireless frequency of the work area, or a square footage of the workarea.
 3. The method of claim 2 wherein determining the placement in thework area of the at least one test radio frequency tag furthercomprises: determining a high traffic area based on the average amountof foot traffic in portions of the work area; and determining theplacement of the at least one test radio frequency tag as proximal tothe high traffic area.
 4. The method of claim 2 wherein determining thenumber of the plurality of access points to position in the work areafurther comprises determining the number of the plurality of accesspoints to position in the work area based the square footage of the workarea.
 5. The method of claim 1 wherein the infrastructure attributescomprise at least one of a location of power outlets or a location ofwired Ethernet outlets.
 6. The method of claim 1 wherein the thresholdis satisfied when the at least one test radio frequency tag receivescoverage from at least three of the plurality of access points.
 7. Themethod of claim 1 further comprising receiving an indication of anactual physical location of the at least one test radio frequency tag inthe work area.
 8. The method of claim 7 further comprising: determiningan expected location of the at least one test radio frequency tag basedon readings of the plurality of access points; and determining theaccuracy of locating the at least one test radio frequency tag bycomparing the actual physical location of the at least one test radiofrequency tag to the expected location of the at least one test radiofrequency tag.
 9. The method of claim 8 wherein the threshold issatisfied when the expected location of the at least one test radiofrequency tag is within a distance of the actual physical location ofthe at least one test radio frequency tag.
 10. The method of claim 1further comprising adding additional access points to the work area whenthe coverage and the accuracy of locating the at least one test radiofrequency tag do not satisfy the threshold.
 11. The method of claim 1further comprising: testing the positioning of the plurality of accesspoints in the work area to determine the coverage and the accuracy oflocating the at least one radio frequency test tag in the work area; anddetermining whether the positioning of the coverage and the accuracy oflocating the at least one radio frequency test tag satisfies thethreshold.
 12. The method of claim 1, wherein determining thepositioning of the plurality of access points in the work area furthercomprises determining the positioning of the plurality of access pointsin the work area based on the architectural attributes, theinfrastructure attributes, and the placement of the at least one testradio frequency tag.
 13. The method of claim 1 further comprisingperforming one or more verification tests to verify the positioning ofthe plurality of access points.
 14. A method for re-using mobile accesspoints to determine a relative positioning of access points in a realtime locating system, the method comprising: receiving layoutinformation of a work area, wherein the layout information comprisesarchitectural attributes and infrastructure attributes of the work area;partitioning the work area into a plurality of partitions based on thearchitectural attributes and the infrastructure attributes; determininga placement of at least one test radio frequency tag in each of theplurality of partitions, wherein the determining is based on thearchitectural attributes; determining, by a processor, a number and apositioning of a plurality of access points for each of the plurality ofpartitions, wherein the determining is based on the architecturalattributes, the infrastructure attributes, and the placement of the atleast one test radio frequency tag in each of the plurality ofpartitions; positioning a plurality of mobile access points in thedetermined positioning of the plurality of access points for each of theplurality of partitions; testing a coverage and an accuracy of each ofthe plurality of partitions, wherein the plurality of partitions aretested serially and the plurality of mobile access points are re-usedfor testing each of the plurality of partitions; and providing agraphical representation of the positioning of each of the plurality ofaccess points in each of the plurality of partitions of the work area.15. The method of claim 14 wherein the mobile wireless access pointcomprises a battery capable of independently powering the mobilewireless access point.
 16. The method of claim 14 wherein thearchitectural attributes comprise at least one of a number of levels ofthe work area, a height of a level, an average amount of foot traffic ina portion of the work area, a wireless frequency of the work area, or asquare footage of the work area.
 17. The method of claim 14 wherein theinfrastructure attributes comprise at least one of a location of poweroutlets or a location of wired Ethernet outlets.
 18. A system forrelative positioning of access points in a real time locating system,the system comprising: a memory to store layout information of a workarea, wherein the layout information comprises architectural andinfrastructure attributes of the work area; an interface operativelyconnected to the memory, the interface operative to receive the layoutinformation of the work area; and a processor operatively connected tothe memory and the interface, the processor operative to receive, viathe interface, the layout information of the work area, determine anumber of a plurality of access points to position in the work areabased on the architectural attributes of the work area, determine aplacement in the work area of at least one test radio frequency tagbased on the infrastructure attributes of the work area, determine apositioning of the plurality of access points in the work area, whereinthe positioning substantially maximizes a coverage and an accuracy oflocating the at least one test radio frequency tag in the work area,determine a repositioning of at least one of the plurality of accesspoints when the coverage and accuracy do not satisfy a threshold, andprovide a graphical representation of the positioning of each of theplurality of access points in the work area, relative to one another,when the coverage and the accuracy satisfy the threshold.
 19. The systemof claim 18 wherein the architectural attributes comprise at least oneof a number of levels of the work area, a height of a level, an averageamount of foot traffic in portions of the work area, a wirelessfrequency of the work area, or a square footage of the work area. 20.The system of claim 19 wherein the processor determines a high trafficarea based on the average amount of foot traffic in portions of the workarea, and determines the placement of the at least one test radiofrequency tag as proximal to the high traffic area.
 21. The system ofclaim 19 wherein the processor determines the number of the plurality ofaccess points to position in the work area based the square footage ofthe work area.
 22. The system of claim 18 wherein the infrastructureattributes comprise at least one of a location of power outlets or alocation of wired Ethernet outlets.
 23. The system of claim 18 whereinthe processor determines the positioning of the plurality of accesspoints in the work area based on the architectural attributes, theinfrastructure attributes, and the placement of the at least one testradio frequency tag.
 24. The system of claim 18 wherein the processorperforms one or more verification tests to verify the positioning of theplurality of access points.